Absorbent article with multiple zone structural elastic-like film web extensible waist feature

ABSTRACT

Disclosed is a nonwoven web comprising a plurality of first regions and a plurality of second regions comprised of the same material and being visually distinct from each other, wherein the first regions will exhibit resistive forces in response to an applied elongation along at least one axis before a substantial portion of the second regions develop significant resistive forces to the applied elongation.

CROSS REFERENCE TO RELATED APPLICATION

[0001] This application is a continuation of and claims priority to U.S.application Ser. No. 09/353,559, filed Jul. 14, 1999; which is adivisional of and claims priority to U.S. application Ser. No.08/665,935, filed Jun. 19, 1996, now U.S. Pat. No. 5,947,948; which is adivisional of and claims priority to U.S. application Ser. No.08/203,456, filed Feb. 28, 1994, now U.S. Pat. No. 5,554,145.

FIELD OF THE INVENTION

[0002] The present invention relates to absorbent articles such asdiapers, incontinent briefs, training pants, and the like, and moreparticularly, to absorbent articles having an extensible waist featureproviding dynamic fit about the wearer as well as improved containmentcharacteristics of the absorbent article.

BACKGROUND OF THE INVENTION

[0003] Infants and other incontinent individuals wear absorbent articlessuch as diapers to receive and contain urine and other body exudates.Absorbent articles function both to contain the discharged materials andto isolate these materials from the body of the wearer and from thewearer's garments and bed clothing. Disposable absorbent articles havingmany different basic designs are known to the art. For example, U.S.Pat. Re. 26,152, entitled “Disposable Diaper” issued to Duncan and Bakeron Jan. 31, 1967, describes a disposable diaper which has achieved wideacceptance and commercial success. U.S. Pat. No. 3,860,003, entitled“Contractable Side Portions For Disposable Diaper”, issued to Buell onJan. 14, 1975, describes an elasticized leg cuff disposable diaper whichhas achieved wide acceptance and commercial success.

[0004] However, absorbent articles have a tendency to sag or gap awayfrom and to slide/slip down on the body of the wearer during wear. Thissagging/gapping and sliding/slipping is caused by the relative motionsof the wearer as the wearer breathes, moves and changes positions, bythe downward forces generated when the absorbent article is loaded withbody exudates, and by the rib-like element of the materials of theabsorbent article itself when subjected to such wearer's motions. Thissagging/gapping and sliding/slipping of the absorbent article can leadto premature leakage and poor fit of the absorbent article about thewearer in the waist regions and the leg regions of the absorbentarticle.

[0005] In order to more snugly fit absorbent articles about the wearer,certain commercially available absorbent articles have been providedwith elastic features. An example of a disposable diaper with elasticside panels is disclosed in U.S. Pat. No. 5,151,092, entitled “AbsorbentArticle With Dynamic Elastic Waist Feature Having Predisposed FlexuralHinge” issued to Buell, Clear, and Falcone on Sep. 22, 1992. However,elastics are costly and require a certain degree of manipulation andhandling during assembly. Further, while elastics do provide a degree ofstretch for the absorbent article, the components of the absorbentarticle to which the elastics are attached are typically not elasticsuch that the elastics must be prestretched prior to being secured tothe absorbent article or the inelastic components must be subjected tomechanical stretching (e.g., ring rolling) to enable the added elasticto be effective. Otherwise, the added elastic is restrained by theinelastic components.

[0006] Therefore, it is an object of the present invention to provide arelatively low cost, easy to manufacture, absorbent article havingsustained dynamic fit about the wearer during use.

[0007] It is a further object of the present invention to provide anabsorbent article having a unique extensible waist feature, preferablywithout the use of elastic, that provides sustained dynamic fit andimproved resistance to leakage during use due to the conformability ofthe materials forming the waist feature by virtue of their readilyextensible nature.

[0008] It is a still further object of the present invention to providean extensible waist feature on an absorbent article that exhibits an“elastic-like” behavior in the direction of applied force or elongationwithout the use of additional elastic material.

[0009] It is an even further object of the present invention to providean extensible back waist feature on an absorbent article that enhancesfit and containment by providing multiple zones or panels havingdifferent force/extension properties to better distribute the forcesencountered by the back waist feature during use and provide thenecessary stretch and extension characteristics in those zones.

[0010] These and other objects of the present invention will be morereadily apparent when considered in reference to the followingdescription and when taken in conjunction with the accompanyingdrawings.

SUMMARY OF THE INVENTION

[0011] The present invention provides absorbent articles such asdisposable diapers, incontinent briefs, diaper holders, training pants,feminine hygiene garments and the like, that have an extensible backwaist feature that improves the dynamic fit as well as the containmentcharacteristics of the absorbent article. Such absorbent articlescomprise a chassis assembly preferably comprising a liquid pervioustopsheet, a liquid impervious backsheet, and an absorbent corepositioned between the topsheet and the backsheet; an extensible backwaist feature having multiple panels or zones; and a closure system formaintaining the absorbent article on the wearer.

[0012] In a preferred embodiment of the present invention, the absorbentarticle has a T-shape comprising a chassis assembly and a extensibleback waist feature disposed in the back waist region. The extensibleback waist feature provides an extensible member that provides a morecomfortable and contouring fit by initially conformably fitting thediaper to the wearer and by sustaining this fit. The extensible backwaist feature further develops and maintains wearing forces (tensions)that enhance the tensions developed and maintained by the closuresystem. The extensible back waist feature further provides moreeffective application of the diaper. The extensible back waist featurehas a central waistband panel, a pair of side panels, and a hip panel.Each of the panels are designed to provide different force and extensionproperties to optimize the fit of the diaper. While each panel of theextensible back waist feature may be constructed from a number ofextensible materials, they preferably each comprise a structuralelastic-like film (SELF) web since a SELF web allows the force/extensioncharacteristics to be specifically designed for each panel and with aminimum amount of materials (no conventional elastic materials need tobe used).

[0013] A structural elastic-like film (SELF) web exhibits anelastic-like behavior in the direction of elongation without the use ofadded elastic materials. SELF webs exhibit at least two significantlydifferent stages of controlled resistive force to elongation along atleast one predetermined axis when subjected to an applied elongation ina direction parallel to the predetermined axis. SELF webs include astrainable network having at least two contiguous, distinct, anddissimilar regions. One of the regions is configured so that it willexhibit resistive forces in response to the applied axial elongation ina direction parallel to the predetermined axis before a substantialportion of the other region develops significant resistive forces to theapplied elongation. At least one of the regions has a surface-pathlengthwhich is greater than that of the other region as measured substantiallyparallel to the predetermined axis while the material is in anuntensioned condition. The region exhibiting the longersurface-pathlength includes one or more rib-like elements which extendbeyond the plane, of the other region. SELF webs exhibit first resistiveforces to the applied elongation until the elongation of the web issufficient to cause a substantial portion of the region having thelonger surface-pathlength to enter the plane of applied elongation,whereupon the SELF web exhibits second resistive forces to furtherelongation. The total resistive forces to elongation are higher than thefirst resistive forces to elongation provided by the first region.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] While the specification concludes with claims particularlypointing out and distinctly claiming the subject matter which isregarded as forming the present invention, it is believed that theinvention will be better understood from the following description whichis taken in conjunction with the accompanying drawings in which likedesignations are used to designate substantially identical elements, andin which:

[0015]FIG. 1 is a plan view of a disposable diaper embodiment of thepresent invention having portions cut-away to reveal underlyingstructure, the outer surface of the diaper facing the viewer;

[0016]FIG. 1A is a simplified plan view of the disposable diaperembodiment of FIG. 1 depicting the various panels of the diaper;

[0017]FIG. 2 is a cross-sectional view of the disposable diaperembodiment of FIG. 1 taken through Line 2-2 in FIG. 1;

[0018]FIG. 3 is a plan view of the disposable diaper embodiment of FIG.1 in its stretched condition with forces applied to the side panels;

[0019]FIG. 4 is a blown up plan view of a portion of the disposablediaper of FIG. 1 showing the details of the SELF webs of the extensibleback waist region and the relative positioning of the elements of thediaper;

[0020]FIG. 5 is a plan view photograph of a preferred embodiment of aSELF web having a strainable network of the present invention with therib-like elements facing toward the viewer;

[0021]FIG. 5A is a segmented, perspective illustration of the SELF webof FIG. 5 in an untensioned condition;

[0022]FIG. 5B is a segmented, perspective illustration of the SELF webof FIG. 5 in a tensioned condition corresponding to stage I on theforce-elongation curve depicted in FIG. 6;

[0023]FIG. 5C is a segmented perspective illustration of the SELF web ofFIG. 5 in a tensioned condition corresponding to stage II on theforce-elongation curve depicted in FIG. 6;

[0024]FIG. 6 is a graph of the resistive force versus percent elongationcomparing the behavior of the SELF web of the present invention as shownin FIG. 5, with an otherwise identical, planar, base polymeric webmaterial;

[0025]FIG. 7 is a graph of the elastic hysteresis behavior of the SELFweb of FIG. 6 when subjected to 60% elongation and examined forhysteresis response;

[0026]FIG. 8 is a simplified side elevational view of a preferredapparatus used to form that portion of the SELF web of the presentinvention;

[0027]FIG. 9 is a plan view of the opposed meshing plates of theapparatus of FIG. 8 laid side-by-side with their meshing surfacesexposed;

[0028]FIG. 10 is a simplified side elevational view of a static pressused to form at least a portion of the base film into a SELF web of thepresent invention;

[0029]FIG. 11 is a simplified side elevational view of a continuous,dynamic press used to form predetermined portions of the base film intoa SELF web of the present invention;

[0030]FIG. 12 is a simplified illustration of an apparatus used to format least a portion of a base film into a SELF web of the presentinvention;

[0031]FIG. 13 is a simplified illustration of yet another apparatus usedto form at least a portion of a base film into a SELF web of the presentinvention;

[0032]FIG. 14 is a graph of the resistive force vs. percent elongationcomparing the behavior of an alternative SELF web material which is alaminate comprised of a layer of a polymeric film and a nonwoven layersecured by adhesive having a strainable network of the present inventionto the otherwise identical unformed, planar, base web material;

[0033]FIG. 15 is a graph of the elastic hysteresis behavior of the webmaterial having the strainable network of FIG. 14 when subjected to 60%percent elongation and examined for elastic hysteresis response;

[0034]FIG. 16 is a simplified plan view of an alternative disposablediaper embodiment of the present invention generally showing thedirection of extensibillity of the panels of the extensible back waistregion;

[0035]FIG. 17 is a simplified close up plan view of an alternativeconfiguration of the side panel of the disposable diaper embodiment ofthe present invention;

[0036]FIG. 18 is a plan view of a still alternative disposable diaperembodiment of the present invention;

[0037]FIG. 19 is a plan view of the alternative disposable diaperembodiment of FIG. 18 showing the diaper in its stretched condition whenforces are applied to the side panels and to the front waist feature;

[0038]FIG. 20 is a partially cut-away plan view of an alternativedisposable diaper embodiment of the present invention having anhourglass shape and an extensible front waist feature of a SELF web;

[0039]FIG. 21 is a fragmentary plan view of an alternative extensiblefront waist feature of the present invention;

[0040]FIG. 22 is a fragmentary plan view of a further alternativeextensible front waist feature of the present invention;

[0041]FIG. 23 is a fragmentary plan view of a still further alternativeextensible front waist feature of the present invention; and

[0042]FIG. 24 is a fragmentary plan view of an even still furtheralternative extensible front waist feature of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0043] As used herein, the term “absorbent article” refers to deviceswhich absorb and contain body exudates, and, more specifically, refersto devices which are placed against or in proximity to the body of thewearer to absorb and contain the various exudates discharged from thebody. The term “disposable” is used herein to describe absorbentarticles which are not intended to be laundered or otherwise restored orreused as an absorbent article (i.e., they are intended to be discardedafter a single use and, preferably, to be recycled, composted orotherwise disposed of in an environmentally compatible manner). A“unitary” absorbent article refers to absorbent articles which areformed of separate parts united together to form a coordinated entity sothat they do not require separate manipulative parts like a separateholder and liner. A preferred embodiment of an absorbent article of thepresent invention is the unitary disposable absorbent article, diaper20, shown in FIG. 1. As used herein, the term “diaper” refers to anabsorbent article generally worn by infants and incontinent persons thatis worn About the lower torso of the wearer. It should be understood,however, that the present invention is also applicable to otherabsorbent articles such as incontinent briefs, training pants, femininehygiene garments, and the like.

[0044]FIG. 1 is a plan view of the diaper 20 of the present invention inits flat-out, uncontracted state (i.e., with elastic induced contractionpulled out) with portions of the structure being cut-away to moreclearly show the construction of the diaper 20 and with the portion ofthe diaper 20 which faces away from the wearer, the outer surface,facing the viewer. As shown in FIG. 1, the diaper 20 has a generally“T-shape” and comprises a chassis assembly 22 preferably comprising aliquid pervious topsheet 24, a liquid impervious backsheet 26 joinedwith the topsheet 24, an absorbent core 28 positioned between thetopsheet 24 and the backsheet 26; extensible leg cuffs 30 eachcomprising a leg flap panel 31 and one or more elastic members, elasticstrands 54, operatively joined with the leg flap panel 31; an extensibleback waist feature 32 comprising a central waistband panel 34, a pair ofside panels 36, and a hip panel 38; a closure system for fastening thediaper on the wearer preferably comprising at least a pair of tape tabs40 and a landing member preferably comprising a reinforcing strip 41;and an extensible front waist feature 42 comprising a front waist panel43.

[0045]FIG. 1A shows a simplified plan view of the disposable diaper ofFIG. 1 depicting the various panels of the diaper 20 and theirpositioning with respect to each other. The diaper 20 comprises achassis assembly or chassis panel 22, a pair of leg flap panels 31, afront waist panel 43, a hip panel 38, a central waistband panel 34, anda pair of side panels 36. The chassis panel or chassis assembly 22 isthe main portion of the diaper from which the other panels emanate. Theabsorbent core is generally positioned within the chassis panel althoughit may extend into other panels or zones of the diaper. A leg flap panel31 extends generally laterally outwardly from and along eachlongitudinal edge 23 of the chassis panel 22. The leg flap panel 31forms at least a portion of the leg cuff 30. As shown in FIG. 1A, theelastic strands 54 are operatively joined to the leg flap panel 31 toform an extensible leg cuff 30. The front waist panel 43 extendsgenerally longitudinally outwardly from and along the lateral edge 23′of the chassis panel 22 and preferably each leg flap panel 31 in thefront waist region. The front waist panel 43 generally forms theextensible front waist feature of the diaper. The hip panel 38 extendsgenerally longitudinally outwardly from and along the lateral edge 23′of the chassis panel 22 and preferably each leg flap panel 31 in theback waist region. The hip panel 38 forms a portion of the extensibleback waist feature. The central waistband panel 34 extends generallylongitudinally outwardly from and along the hip panel 38. The centralwaistband panel 34 also forms a portion of the extensible back waistfeature. The side panels 36 each extend generally laterally outwardlyfrom and along the central waistband panel 34 and at least a portion ofthe hip panel 38. The side panels 36 also form a portion of the backextensible waist feature.

[0046] As discussed hereinafter, each of the panels may be a separatemember joined to the overall diaper structure or may be unitary with thediaper in that they comprise an extension of other elements of thediaper such as the topsheet, the backsheet, or both. In the embodimentshown in FIG. 1, all of the panels except for the side panels 36comprise an extension of the topsheet 24 and the backsheet 26. The sidepanels 36 comprise a separate member joined to the central waistbandpanel 34 and at least a portion of the hip panel 38. Further, any or allof the panels may be extensible. The chassis panel 22 is typically notextensible in order to maintain the integrity of the absorbent core 28during use, although it may be rendered extensible such as by beingformed as a structural elastic-like film (SELF) web as described herein.Preferably, the extensible panels comprise a SELF web. The use of a SELFweb allows the force/extension properties of each of the panels to bespecifically designed to maximize the fit and containment of the diaperwith a minimum amount of materials (no conventional elastic materialsare needed).

[0047] The diaper 20 of FIG. 1 has an inner surface (not shown), anouter surface 44 (facing the viewer in FIG. 1) opposed to the innersurface, a front waist region 45, a back waist region 46 opposed to thefront waist region 45, and a periphery which is defined by the outeredges of the diaper 20 in which the longitudinal edges are designated 47and the end edges are designated 48. (While the skilled artisan willrecognize that a diaper is usually described in terms of having a pairof waist regions and a crotch region between the waist regions; in thisapplication, for simplicity of terminology, the diaper 20 is describedas having only waist regions, each of the waist regions including aportion of the diaper which would typically be designated as part of thecrotch region). The inner surface of the diaper 20 comprises thatportion of the diaper 20 which is positioned adjacent to the wearer'sbody during use (i.e., the inner surface generally is formed by at leasta portion of the topsheet 24 and other components joined to the topsheet24). The outer surface 44 comprises that portion of the diaper 20 whichis positioned away from the wearer's body (i.e., the outer surface 44generally is formed by at least a portion of the backsheet 26 and othercomponents joined to the backsheet 26). The front waist region 45 andthe back waist region 46 extend, respectively, from the end edges 48 ofthe periphery to the lateral centerline 49 of the diaper 20. (Thelateral direction (x direction or width) is defined as the directionparallel to the lateral centerline 49 of the diaper 20; the longitudinaldirection (y direction or length) being defined as the directionparallel to the longitudinal centerline 50; and the axial direction (Zdirection or thickness) being defined as the direction extending throughthe thickness of the diaper 20.)

[0048]FIG. 1 shows a preferred embodiment of the diaper 20 in which thetopsheet 24 and the backsheet 26 have length and width dimensionsgenerally larger than those of the absorbent core 28. The topsheet 24and the backsheet 26 extend beyond the edges of the absorbent core 28 tothereby form certain of the panels and portions of the periphery of thediaper. The periphery defines the outer perimeter or, in other words,the edges of the diaper 20. The periphery comprises the longitudinaledges 47 and the end edges 48.

[0049]FIG. 2 is a cross-sectional view of the diaper embodiment of FIG.1 of the present invention taken through line 2-2 of FIG. 1. FIG. 2shows the chassis assembly 22 comprising a portion of the topsheet 24, aportion of the backsheet 26, and the absorbent core 28 positionedbetween the topsheet 24 and the backsheet 26. In the embodiment shown inFIG. 2, the hip panel 38 is joined to and extends longitudinallyoutwardly from the chassis assembly 22, preferably from the waist edge56 of the absorbent core 28. The hip panel 38 is unitary with thechassis assembly 22 and comprises a structural elastic-like film (SELF)web comprising the portion of the topsheet and the backsheet extendinglongitudinally beyond the waist edge. Thus, the extensibility of the hippanel is achieved without the use of a separate elastic materialoperatively joined to the topsheet and the backsheet. The centralwaistband panel 34 is joined to and extends longitudinally outwardlyfrom the hip panel 38. The central waistband panel is unitary with thehip panel, and thus the chassis assembly in this embodiment, andcomprises a SELF web comprising the portion of the topsheet and thebacksheet. The bands 64′ of the central waistband pane SELF web are,preferably wider (longitudinal dimension) than the bands 64″ of the hippanel SELF web with the pleats 66′ of the waistband panel SELF web beingpreferably wider than the pleats 66″ of the hip panel SELF web. Thus,the extension forces of the central waistband panel SELF web are higherthan the extension forces of the hip panel SELF web.

[0050] The chassis assembly 22 (chassis panel) of the diaper 20 is shownin FIGS. 1 and 1A as comprising the main body (chassis) of the diaper20. The chassis assembly 22 comprises at least an absorbent core 28,preferably an outer covering layer comprising the topsheet 24 and thebacksheet 26. Thus, the chassis assembly 22 comprises the main structureof the diaper with other features added to form the composite diaperstructure. An exemplary example of a chassis assembly of the presentinvention is described in U.S. Pat. No. 3,860,003 issued to Kenneth B.Buell on Jan. 14, 1975, which patent is incorporated herein byreference.

[0051] The absorbent core 28 may be any absorbent means which is capableof absorbing and retaining liquids such as urine and other certain bodyexudates. The absorbent core 28 has a garment surface, a body surface,side edges 57, and waist edges 56. The absorbent core 28 may bemanufactured in a wide variety of sizes and shapes (e.g., rectangular,hourglass, “T”-shaped, asymmetric, etc.) and from a wide variety ofliquid-absorbent materials commonly used in disposable diapers and otherabsorbent articles such as comminuted wood pulp which is generallyreferred to as airfelt. Examples of other suitable absorbent materialsinclude creped cellulose wadding, meltblown polymers including coform,cross-linked cellulose fibers, tissue including tissue wraps and tissuelaminates, absorbent foams, absorbent sponges, superabsorbent polymers,absorbent gelling materials, or any equivalent material or combinationsof materials. The configuration and construction of the absorbent coremay also be varied (e.g., the absorbent core may have varying caliperzones, a hydrophilic gradient, a superabsorbent gradient, or loweraverage density and lower average basis weight acquisition zones; or maycomprise one or more layers or structures). The total absorbent capacityof the absorbent core 28 should, however, be compatible with the designloading and the intended use of the diaper 20. Further, the size andabsorbent capacity of the absorbent core 28 may be varied to accommodatewearers ranging from infants through adults. FIG. 1 shows a preferredembodiment of the diaper 20 having a rectangular-shape absorbent core.

[0052] An absorbent structure useful as the absorbent core 28 of thepresent invention that has achieved wide acceptance and commercialsuccess is described in U.S. Pat. No. 4,610,678 entitled “High-DensityAbsorbent Structures” issued to Weisman and Goldman on Sep. 9, 1986.U.S. Pat. No. 4,673,402 entitled “Absorbent Articles With Dual-LayeredCores” issued to Weisman, Houghton, and Gellert on Jun. 16, 1987; U.S.Pat. No. 4,888,231 entitled “Absorbent Core Having A Dusting Layer”issued to Angstadt on Dec. 19, 1989; U.S. Pat. No. 5,147,345 entitled“High Efficiency Absorbent Articles For Incontinence Management”, issuedto Young, LaVon & Taylor on Sep. 15, 1992; U.S. Pat. No. 5,102,597entitled “Porous, Absorbent, Polymeric Macrostructures and Methods OfMaking the Same”, issued to Roe, Lahrman and Berg on Apr. 7, 1992; andU.S. Pat. No. 4,834,735, entitled “High Density Absorbent Members HavingLower Density and Lower Basis Weight Acquisition Zones”, issued toAlemany and Berg on May 30, 1989; also describe absorbent structuresthat are useful in the present invention. The absorbent core 28 ispreferably the dual-layer absorbent structure described in U.S. Pat. No.5,234,423 entitled “Absorbent Article With Elastic Waist Feature andEnhanced Absorbency”, issued to Alemany and Clear on Aug. 10, 1993. Eachof these patents are incorporated herein by reference.

[0053] The backsheet 26 is positioned adjacent the garment surface ofthe absorbent core 28 and is preferably joined thereto by attachmentmeans (not shown) such as those well known in the art. For example, thebacksheet 26 may be secured to the absorbent core 28 by a uniformcontinuous layer of adhesive, a patterned layer of adhesive, or an arrayof separate lines, spirals, or spots of adhesive. Adhesives which havebeen found to be satisfactory are manufactured by H. B. Fuller Companyof St. Paul, Minn. and marketed as HL-1258. The attachment means willpreferably comprise an open pattern network of filaments of adhesive asis disclosed in U.S. Pat. No. 4,573,986 entitled “DisposableWaste-Containment Garment”, which issued to Minetola and Tucker on Mar.4, 1986, and which is incorporated herein by reference. An exemplaryattachment means of an open pattern network of filaments comprisesseveral lines of adhesive filaments swirled into a spiral pattern suchas is illustrated by the apparatus and methods shown in U.S. Pat. No.3,911,173 issued to Sprague, Jr. on Oct. 7, 1975; U.S. Pat. No.4,785,996 issued to Ziecker, et al. on Nov. 22, 1978; and U.S. Pat. No.4,842,666 issued to Werenicz on Jun. 27, 1989. Each of these patents areincorporated herein by reference. Alternatively, the attachment meansmay comprise heat bonds, pressure bonds, heat/pressure bonds, ultrasonicbonds, dynamic mechanical bonds, or any other suitable attachment meansor combinations of these attachment means as are known in the art.

[0054] The backsheet 26 is impervious to liquids (e.g., urine) and ispreferably manufactured from a thin plastic film, although otherflexible liquid impervious materials may also be used. As used herein,the term “flexible” refers to materials which are compliant and willreadily conform to the general shape and contours of the human body. Thebacksheet 26 prevents the exudates absorbed and contained in theabsorbent core 28 from wetting articles which contact the diaper 20 suchas bedsheets and undergarments. The backsheet 26 may thus comprise awoven or nonwoven material, polymeric films such as thermoplastic filmsof polyethylene or polypropylene, or composite materials such as afilm-coated nonwoven material. Preferably, the backsheet is athermoplastic film having a thickness of from about 0.012 mm (0.5 mil)to about 0.051 mm (2.0 mils). The backsheet preferably comprises apolyethylene blend film of about 0.025 mm (1.0 mil) as is manufacturedby Tradegar Corporation of Terre Haute, Ind. and marketed as P8863.

[0055] The topsheet 24 is positioned adjacent the body surface of theabsorbent core 28 and is preferably joined thereto and to the backsheet26 by attachment means (not shown) such as those well known in the art.Suitable attachment means are described with respect to joining thebacksheet 26 to the absorbent core 28. As used herein, the term “joined”encompasses configurations whereby an element is directly secured to theother element by affixing the element directly to the other element, andconfigurations whereby the element is indirectly secured to the otherelement by affixing the element to an intermediate member(s) which inturn is affixed to the other element. In a preferred embodiment of thepresent invention, the topsheet 24 and the backsheet 26 are joineddirectly to each other in the diaper periphery and are indirectly joinedtogether by directly joining them to the absorbent core 28 by theattachment means (not shown).

[0056] The topsheet 24 is compliant, soft feeling, and non-irritating tothe wearer's skin. Further, the topsheet 24 is liquid perviouspermitting liquids (e.g., urine) to readily penetrate through itsthickness. A suitable topsheet may be manufactured from a wide range ofmaterials, such as porous foams; reticulated foams; apertured plasticfilms; or woven or nonwoven webs of natural fibers (e.g., wood or cottonfibers), synthetic fibers (e.g., polyester or polypropylene fibers), ora combination of natural and synthetic fibers. Preferably, the topsheet24 is made of a hydrophobic material to isolate the wearer's skin fromliquids which have passed through the topsheet and are contained in theabsorbent core 28 (i.e., to prevent rewet). If the topsheet is made of ahydrophobic material, at least the upper surface thereof is treated tobe hydrophilic so that liquids will transfer through the topsheet morerapidly. This diminishes the likelihood that body exudates will flow offthe topsheet rather than being drawn through the topsheet and beingabsorbed by the absorbent core. The topsheet can be rendered hydrophilicby treating it with a surfactant. Suitable methods for treating thetopsheet with a surfactant include spraying the material with thesurfactant and immersing the material in the surfactant. A more detaileddiscussion of such a treatment and hydrophilicity is contained in U.S.Pat. No. 4,988,344 entitled “Absorbent Articles With Multiple LayerAbsorbent Layers” issued to Reising, et al. on Jan. 29, 1991.

[0057] There are a number of manufacturing techniques which may be usedto manufacture the topsheet 24. For example, the topsheet 24 may be anonwoven web of fibers. When the topsheet comprises a nonwoven web, theweb may be spunbonded, carded, wet-laid, meltblown, hydroentangled,combinations of the above, or the like. A preferred topsheet is cardedand thermally bonded by means well known to those skilled in the fabricsart. A preferred topsheet comprises staple length polypropylene fibershaving a denier of about 2.2. As used herein, the term “staple lengthfibers” refers to those fibers having a length of at least about 15.9 mm(0.625 inches). Preferably, the topsheet has a basis weight from about18 to about 25 grams per square meter. A suitable topsheet ismanufactured by Veratec, Inc., a Division of International PaperCompany, of Walpole, Mass. under the designation P-8.

[0058] The diaper 20 preferably further comprises extensible leg cuffs30 for providing improved containment of liquids and other bodyexudates. Each extensible leg cuff 30 may comprise several differentembodiments for reducing the leakage of body exudates in the legregions. (The leg cuff can be and is sometimes also referred to as legbands, leg flaps, barrier cuffs, or elastic cuffs.) U.S. Pat. No.3,860,003 entitled “Contractable Side Portions For a Disposable Diaper”issued to Buell on Jan. 14, 1975, describes a disposable diaper whichprovides a contractible leg opening having a leg flap and one or moreelastic members to provide an elasticized leg cuff (gasketing cuff).U.S. Pat. No. 4,909,803 entitled “Disposable Absorbent Article HavingElasticized Flaps” issued to Aziz & Blaney on Mar. 20, 1990, describes adisposable diaper having “stand-up” elasticized flaps (barrier cuffs) toImprove the containment of the leg regions. U.S. Pat. No. 4,695,278entitled “Absorbent Article Having Dual Cuffs” issued to Lawson on Sep.22, 1987, describes a disposable diaper having dual cuffs including agasketing cuff and a barrier cuff. U.S. Pat. No. 4,704,115 entitled“Disposable Waist Containment Garment” issued to Buell on Nov. 3, 1987,discloses a disposable diaper or incontinent garment havingside-edge-leakage-guard gutters configured to contain free liquidswithin the garment. U.S. Pat. No. 5,032,120 entitled “DisposableAbsorbent Article Having Improved Leg Cuffs” issued to Freeland & Allenon Jul. 16, 1991, discloses an absorbent article having leg cuffs havinga relatively low ultimate contact force at relatively high elongationsaccomplished, for example, by low contact force differential material.U.S. Pat. No. 5,087,255 entitled “Absorbent Article Having InflectedBarrier Cuffs” issued to Sims on Feb. 11, 1992, discloses an absorbentarticle having inflected barrier cuffs with the distal edge positionedoutboard of the proximal edge in one waist region and inboard in theother to provide better fit about the hips/buttocks. Each of thesepatents are incorporated herein by reference. While each extensible legcuff 30 may be configured so as to be similar to any of the leg bands,leg flaps, barrier cuffs, or elastic cuffs described above, as shown inFIG. 1, each extensible leg cuff 30 comprises the leg flap panel 31extending laterally outwardly from the chassis panel 22, the side edge57 of the absorbent core 28, and one or more elastic members, elasticstrands 54, operatively joined with the leg flap panel 31, such as isdescribed in the above-referenced U.S. Pat. No. 3,860,003.

[0059] The diaper 20 further comprises extensible waist features thatprovide improved fit and containment. The extensible waist features atleast extend longitudinally outwardly from the chassis assembly,preferably a respective waist edge of the absorbent core 28, andgenerally form at least a portion of the end edge of the diaper 20.Thus, in the embodiment shown in FIG. 1, the extensible back waistfeature 32 comprises that portion of the diaper 20 extending from thewaist edge 56 of the absorbent core 28 in the back waist region 46 tothe end edge 48 of the diaper 20. While a disposable diaper of thepresent invention is constructed with an extensible waist featuredisposed in each waist region (an extensible back waist feature 32 andan extensible front waist feature 42), the discussion will focus ondiapers having different configurations for each extensible waistfeature. At a minimum, it is preferred that the diaper at least have oneof the extensible waist features constructed according to the presentinvention, more preferably at least the back extensible waist feature32. The waist features can be constructed as a separate element joinedto the chassis assembly 22 or as an extension of other elements of thediaper (i.e., unitary). The waist features will be described withrespect to preferred embodiments in which certain portions or panelscomprise an extension of other elements of the diaper such as thebacksheet 26, the topsheet 24, or both, and other portions or panelscomprise a separate element joined to other portions or panels of thewaist feature or other panels of the diaper.

[0060] The extensible back waist feature 32 provides an extensiblemember that provides a more comfortable and contouring fit by initiallyconformably fitting the diaper to the wearer and sustaining this fitthroughout the time of wear well past when the diaper has been loadedwith exudates since the extensible back waist feature allows the diaperto expand and, preferably, to contract. Further, the extensible backwaist feature develops and maintains wearing forces (tensions) thatenhance the tensions developed and maintained by the closure system tomaintain the diaper on the wearer and that enhance the fit of the diaperabout the waist of the wearer. The extensible back waist feature furtherprovides more effective application of the diaper since even if thediaperer pulls one side (side panel 36) of the extensible back waistfeature farther than the other during application (asymmetrically), thediaper will “self-adjust” during wear.

[0061] As shown in FIG. 1, the extensible back waist feature 32comprises a central waistband panel 34; a pair of side panels 36; and ahip panel 38. In the embodiment shown in FIG. 1, the hip panel 38 isdisposed longitudinally outwardly from the chassis assembly 22 (thechassis panel), preferably from the waist edge 56 of the absorbent core28, in the middle zone of the back waist region 46; the centralwaistband panel 34 is disposed longitudinally outwardly from the hippanel 38; and the side panels 36 are each disposed laterally outwardlyfrom the central waistband panel 34 and at least a portion of the hippanel 38. As discussed hereinafter, the particular positioning of eachpanel of the back waist feature is important to the overall functioningof the back waist feature. The term “panel” is used herein to denote anarea or element of the waist feature or diaper. (While a panel istypically a distinct area or element, a panel may overlap somewhat withan adjacent panel.)

[0062] Each of the panels of the back waist feature 32 is extensible soas to dynamically fit and conform to the wearer so as to provide suchimproved fit and containment. The force/extension properties orcharacteristics (e.g., extension forces, available stretch (extension),and contractive force(s)) of each of the panels is specifically designedso as to dynamically expand and move with the movements of the body ofthe wearer adjacent that panel to enhance fit and containment. Asdiscussed hereinafter, since each panel preferably comprises a SELF webas disclosed hereinafter and has a specific and different function, theconfiguration of and materials comprising the SELF web of each panel arespecially selected to provide the different force and extensionrequirements of each panel, thus enhancing the functioning of diaper.

[0063] The hip panel 38 is joined to the chassis assembly 22 and isdisposed longitudinally between the central waistband panel 34 and thelateral centerline 49, preferably the waist edge 56 of the absorbentcore 28 as is shown in FIG. 1, and laterally between the side panels 36.The hip panel 38 is extensible in a direction having a vector componentin the lateral direction, preferably in the lateral direction, toprovide a more comfortable and contouring fit about the hips andbuttocks of the wearer by initially conformably fitting the diaper tothe hips/buttocks and sustaining this fit throughout the time of wearsince the hip panels allow portions of the diaper to expand with thebody and return to its original configuration as the body moves. Thisadditional extensibility in the middle/back of the diaper allows thediaper to better wrap around the wearer's hips and buttocks. As aresult, the diaper fits better to the body and reduces sagging, gappingand slippage. The hip panel is designed to have lower extension forcesthan the central waistband panel, and preferably the side panels, withhigher extension capability, available stretch. This enables the diaperto fit wider at the hips than in the central waistband panel, thusreducing the amount of material that is needed to construct the diaperto provide adequate fit and coverage. Preferably, the extension force ofthe central waistband panel is at least about 2 times, more preferablybetween 2 to 20 times, most preferably between 5 to 10 times, greaterthan the extension force of the hip panel. (The extension force of thehip panel should be as low as possible.) In a preferred embodiment, theextension force of the hip panel is less than about 10 g/cm, preferablyless than about 5 g/cm, at 50% extension. The hip panel 38, as shown inFIG. 3, thus flairs out after the diaper is applied thereby directingthe forces generated in the side panels 36 to transfer to the centralwaistband panel 34. The hip panel 38 also couples the elastic strands 54with the waist closure.

[0064] The hip panel 38 may take on a number of different sizes andshapes. For example, the hip panel may have a trapezoidal, arcuate, orcomplex shape., As shown in FIG. 1A, the hip panel 38 preferably has arectangular shape to minimize material and processing costs. The size ofthe hip panel may also widely vary, depending upon its availablestretch, so long as it provides fit and containment at the hips. In apreferred embodiment of a large (8 kg to 14 kg) baby diaper, the hippanel may, for example, have a size typically about 65 mm long(longitudinal direction) and about 180 mm wide (lateral direction).

[0065] The hip panel 38 is extensible in at least one direction,preferably in a direction having a vector component in the lateraldirection, more preferably in the lateral direction, to provide betterfit by providing extension that follows the hips/buttocks. It should benoted, however, that the hip panel may be extensible in any otherdirection or in more than one direction. In addition, the hip panel mayhave one or more discrete zones of extensibility. For example, in oneembodiment, the hip panel may have a pair of extensible zones, eachpositioned laterally outwardly from a central nonextensible zone orpanel. In the embodiment shown in FIGS. 1 and 4, the central zone isextensible while the lateral zones are nonextensible. Alternatively, theentire hip panel is extensible to provide the desired functions asdescribed herein.

[0066] The hip panel 38 may be constructed in a number ofconfigurations. For example, the hip panel can be constructed of any ofthe various elastomeric materials or elastomeric laminates as are knownin the art. An exemplary elastomeric material is a zero strain stretchlaminate such as described in above-referenced U.S. Pat. No. 5,151,092(Buell, et al.). In an especially preferred embodiment, the hip panelcomprises a SELF web as described hereinafter.

[0067] The hip panel 38 may comprise a separate element affixed to thechassis panel 22 and the side panels 36 and/or central waistband panel34 or can be constructed as an extension of other elements of the backwaist feature or the diaper such as the backsheet 26 or the topsheet 24,preferably both the topsheet and the backsheet, In the embodiment of thepresent invention shown in FIG. 1, the hip panel 38 comprises a portionof the topsheet 24 and a portion of the backsheet 26 formed into a SELFweb as described hereinafter.

[0068] The central waistband panel 34 is the primary component of theextensible back waist feature 32 that provides waist fit and appearance.(The central waistband panel can also be called the waistband or waistpanel of the back waist feature.) The central waistband panel 34 isjoined to the hip panel 38 and is disposed longitudinally outwardly fromthe hip panel 38 and laterally inwardly of the side panels 36 so as tofit in the upper back or lumbar zone of the wearer. The centralwaistband panel 34 is positioned toward the end edge 48 of the diaper 20to generally define the “central upper segment” of the back waistfeature, and preferably, such as is shown in FIG. 1, forms at least aportion of the end edge 48 of the diaper 20. Thus, the central waistbandpanel 34 provides a member that maintains a defined area coverage,contacts the wearer in the upper back or lumbar zone to snugly fit thewearer, and is extensible, preferably in a direction having a vectorcomponent in the lateral direction, more preferably in the lateraldirection, so as to dynamically move, fit, and conform to the wearer.The extension forces of the central waistband panel need to be high,generally higher than the hip panel and, preferably, higher than theside panels, in order to support the diaper without sagging,particularly after loading. (The extension force of the centralwaistband panel is preferably from about 1 to 2 about times as great asthe extension force of the side panels). The extension forces aretypically between about 10 g/cm to 30 g/cm, preferably between about 15g/cm and 20 g/cm, at 50% extension. The higher extension forces of thecentral waistband panel transfer the majority of forces generated in thefitting of the diaper in the side panels to the waist and upper hipregions of the wearer. This enables the diaper to fit higher on thewearer and to allow the tensional forces (a primary line of tension) tobe directed about the waist of the wearer, typically downward toward theabdominal crease of the wearer, so as to provide a continuous primaryline of tension to hold the diaper on the wearer. This higher fit andcontinuous line of tension maintains the sustained fit of the diaper.This higher fit also reduces skin marking at the legs and thighs of thewearer.

[0069] The central waistband panel 34 may have a number of differentsizes and shapes. For example, the central waistband panel may have anarcuate shape so that forces transmitted through the central waistbandpanel are along a line or zone disposed at an angle to the body of thewearer to fit the diaper into the lumbar curve of the back and to allowthe tensional forces (the primary line of tension) to be directeddownward toward the abdominal crease of the wearer so as to provide acontinuous primary line of tension. Examples of complex shapes usefulfor the shape of the central waistband panel and the back waist featureare disclosed in U.S. patent application Ser. No. 08/044,562 entitled“Fitted Belt For Absorbent Garment” filed by New, et al. on Apr. 7,1993, and U.S. patent application Ser. No. 08/072,300 entitled“Absorbent Articles Providing Sustained Dynamic Fit” filed by LaVon, etal. on Jun. 3, 1993; which are incorporated herein by reference. In apreferred embodiment such as is shown in FIG. 1A, the central waistbandpanel 34 has a rectangular shape. The lateral width of the centralwaistband panel is typically greater than its longitudinal length. For atypical “large” (8 kg to 14 kg) baby diaper, the central waistband panelmay, for example, have a size of about 180 mm in the lateral directionby about 30 mm in the longitudinal direction.

[0070] The central waistband panel 34 may be constructed in a number ofconfigurations and from a number of different materials. For example,the central waistband panel may be elasticized by operatively joining anelastic member thereto such as the elasticized waistbands known in theart and as are disclosed in U.S. Pat. No. 4,515,595 issued to Kievit, etal. on May 7, 1985; and U.S. Pat. No. 5,151,092 issued to Buell, et al.on Sep. 29, 1992; each of which are incorporated herein by reference.Thus, the central waistband panel may be a stretch laminate such as azero strain stretch laminate as is described in U.S. Pat. No. 5,151,092(Buell, et al.). In a preferred embodiment of the present invention, thecentral waistband panel comprises a SELF web as described hereinafter.

[0071] The central waistband panel 34 may comprise a separate elementaffixed to the side panels 36 and/or the hip panel 38 or can beconstructed as an extension of other elements of the back waist featureor the diaper such as the backsheet 26 or the topsheet 24, preferablyboth the topsheet and the backsheet. In the embodiment of the presentinvention shown in FIG. 1, the central waistband panel 34 comprises aportion of the topsheet 24 and a portion of the backsheet 126 formedinto a SELF web as described hereinafter.

[0072] The central waistband panel 34 is extensible in at least onedirection, preferably in a direction having a vector component in thelateral direction, more preferably in the lateral direction, to providebetter fit. It should be noted, however, that the central waistbandpanel may be extensible in any other direction or in more than onedirection. In addition, the central waistband panel may have one or morediscrete zones of extensibility. For example, as is shown in FIG. 4, thecentral waistband panel 34 may have a pair of non-extensible zones, eachpositioned laterally outwardly from a central extensible zone or panel.Alternatively, the entire central waistband panel can be extensible toprovide the desired functions as described herein.

[0073] The side panels 36 are those portions of the extensible backwaist feature 32 that extend laterally outwardly from the centralwaistband panel 34 and at least a portion of the hip panel 38, The sidepanels 36 are each an extensible member that primarily function toprovide a more comfortable and contouring fit by initially conformablyfitting the diaper to the wearer at application and sustaining this fitthroughout the time of wear well past when the diaper has been loadedwith exudates by enlarging the circumference of the diaper at the sides,attaching the back waist region to the front waist region of the diaperto complete a closure for the diaper, and distributing forces along boththe waist and legs to transfer these forces such that there is a snugfit with no skin irritation due to excessive forces on the legs or thewaist. The side panels provide stretch as well as, in preferredembodiments, a contractive force after extension and application. Thus,the side panels provide a more comfortable and contouring fit byallowing the sides of the diaper to expand and contract. The side panelsalso develop and maintain wearing forces (tensions) and enhance thetensions developed and maintained by the closure system to maintain thediaper on the wearer and enhance the fit. The side panels assist inmaintaining the primary line of tension formed by the primary fasteningsystem; allowing the diaper to conformably fit over the hips of thewearer where there is dynamic motion, and initially pretensioning thefront extensible waist feature, if provided on the diaper, since thediaperer typically stretches the side panels when applying the diaper onthe wearer so that when the side panels contract, tension is transmittedfrom the side panels through the waist closure system into theextensible front waist feature. The side panels further provide moreeffective application of the diaper since even if the diaperer pulls oneside panel farther than the other during application, the diaper will“self-adjust” during wear. (While the extensible back waist feature hasside panels; the extensible front waist feature may also have sidepanels, preferably extensible side panels such as are described herein.)

[0074] The side panels 36 may have a number of different sizes andshapes. For example, the side panels may each have an arcuate shape sothat forces transmitted through the side panel are along a line or zonedisposed at an angle to the body of the wearer to fit the diaper intothe lumbar curve of the back and to allow the tensional forces (theprimary line of tension) to be directed downward toward the abdominalcrease of the wearer so as to provide a continuous primary line oftension. Examples of such side panels are described in U.S. patentapplication Ser. No. 08/072,300 entitled “Absorbent Articles ProvidingSustained Dynamic Fit” filed by LaVon, et al. on Jun. 3, 1993; and U.S.patent application Ser. No. 08/155,048 entitled “Absorbent Article WithMulti-Directional Extensible Side Panels” filed by Robles, et al. onNov. 19, 1993; each of which is incorporated herein by reference. In thepreferred embodiment shown in FIG. 1A, the side panels 36 have arectangular shape. For a typical “large” (8 kg to, 14 kg) baby diaper,the side panels may, for example, have a size of about 63 mm in thelateral direction by about 57 mm in the longitudinal direction.

[0075] The side panels 36 may be constructed in a number ofconfigurations and from a number of different materials. Examples ofdiapers with elasticized side panels are disclosed in U.S. Pat. No.4,857,067 issued to Wood, et al. on Aug. 15, 1987; U.S. Pat. No.4,381,781 issued to Sciaffara, et al. on May 3, 1983; U.S. Pat. No.4,938,753 issued to Van Gompel, et al. on Jul. 3, 1990; and thehereinbefore referenced U.S. Pat. No. 5,151,091 issued to Buell, et al.on Sep. 21, 1991; each of which are incorporated herein by reference.Thus, the side panels may comprise conventional elastic materials ormechanically stretched laminates such as a zero strain stretch laminate.In a preferred embodiment of the present invention, the side panelscomprise a SELF web as described hereinafter.

[0076] The side panels 36 may comprise a separate element affixed to theback waist feature 32 at the central waistband panel 34 and the hippanel 38, or can be constructed as an extension of other elements of theback waist feature or the diaper such as the backsheet 26 or thetopsheet 24, preferably both the topsheet and the backsheet. In theembodiment of the present invention shown in FIG. 1, the side panels 36each comprise a separate SELF web joined to the back waist feature (thecentral waistband panel 34 and the hip panel 38). The SELF web of theside panels, as described hereinafter, preferably comprises a laminateof two or more layers, preferably two layers; most preferably a laminateof a layer of a polyethylene blend film such as is marketed by ClopayCorporation of Cincinnati, Ohio as Clopay 1401 and a nonwoven web suchas the P-8 material previously described for use as the topsheet. Theextension force of each side panel is preferably between about 10 g/cmto about 15 g/cm at. 50% extension.

[0077] The side panels 36 are extensible in e least one direction;preferably in a direction having a vector component in the lateraldirection, more preferably in the lateral direction, to provide betterfit. It should be noted, however, that the side panels may be extensiblein any other direction or in more than one direction. In addition, theside panels may have one or more discrete zones of extensibility.Preferably, each entire side panel is extensible to provide the desiredfunctions as described herein.

[0078] While each panel of the back waist feature 32 may be constructedfrom a number of different extensible or elastic materials as are knownin the art, one or more, and preferably each, of the panels of the backwaist feature, for performance and cost reasons, is preferablyconstructed of a structural elastic-like film (SELF) web. (The term“web” herein refers to a sheet-like material comprising a single layerof material or a composite or a laminate of two or more layers.)

[0079]FIG. 5 shows an embodiment of a SELF web 52 (formed web material)of the present invention constructed of a single layer of a formedpolymeric material. The SELF web 52 is shown in its substantiallyuntensioned condition. The web has two centerlines, a first centerline,1, (which is also referred to as an axis, line, or direction “l”) and asecond centerline, t, (which is also referred to as an axis, line ordirection “t”) which is generally perpendicular to the first centerline.The web is comprised substantially of linear low density polyethylene(LLDPE) although it may also be comprised of other polyolefins such aspolyethylenes including low density polyethylene (LDPE), ultra lowdensity polyethylene (ULDPE), high density polyethylene (HDPE) orpolypropylene and/or blends thereof of the above and other materials.Examples of other suitable polymeric materials include, but are notlimited to, polyester, polyurethanes, compostable or biodegradablepolymers, and breathable polymers.

[0080] Referring to FIGS. 5 and 5A, the SELF web includes a “strainablenetwork” of distinct regions. As used herein, the term “strainablenetwork” refers to an interconnected and interrelated group of regionswhich are able to be extended to some useful degree in a predetermineddirection providing the SELF web with an elastic-like behavior inresponse to an applied and subsequently released elongation. Thestrainable network includes at least a first region 64 (also generallyreferred to herein as bands or channels) and a second region 66 (alsogenerally referred to herein as ribs or pleats). The SELF web 52 alsoincludes a transitional region 65 which is at the interface between thefirst region 64 and the second region 66. The transitional region 65will exhibit behavior of both the first region and the second region. Itis recognized that every embodiment of the present invention will have atransitional region, however preferred embodiments of the presentinvention will exhibit elastic-like behavior substantially as a resultof the first region 64 and the second region 66. Therefore, the ensuingdescription of the present invention will be concerned with the behaviorof the SELF web in the first regions and the second regions only and notthe complex behavior of the SELF web in the transitional regions.

[0081] SELF web 52 has a first surface and an opposing second surface.In the preferred embodiment shown in FIGS. 5 and 5A, the strainablenetwork includes a plurality of first regions 64 and a plurality ofsecond regions 66. The first regions 64 have a first axis 68 and asecond axis 69, wherein the first axis 68 is preferably longer than thesecond axis 69. The first axis 68 of the first region 64 issubstantially parallel to the first axis of the SELF web 52 while thesecond axis 69 is substantially parallel to the second axis of the SELFweb 52, The second regions 66 have a first axis 70 and a second axis 71.The first axis 70 is substantially parallel to the first axis of theSELF web 52, while the second axis 71 is substantially parallel to thesecond axis of the SELF web 52. In the preferred embodiment of FIG. 5,the first regions 64 and the second regions 66 are substantially linear,extending continuously in a direction substantially parallel to thefirst axis of the SELF web 52.

[0082] The first region 64 has an elastic modulus E1 and across-sectional area A1, The second region 66 has an elastic modulus E2and a cross-sectional area A2.

[0083] In the illustrated embodiment, the SELF web 52 has been “formed”such that the SELF web 52 exhibits a resistive force along a axis, whichin the case of the illustrated embodiment is substantially parallel tothe first axis of the SELF web, when subjected to an applied axialelongation in a direction substantially parallel to the first axis. Asused herein, the term “formed” refers to the creation of a desiredstructure or geometry upon the SELF web that will substantially retainthe desired structure or geometry when it is not subjected to anyexternally applied elongations or forces. A SELF web of the presentinvention is comprised of at least a first region and a second region,wherein the first region is visually distinct from the second region. Asused herein, the term “visually distinct” refers to features of the SELFweb which are readily discernible to the normal naked eye when the SELFweb or objects embodying the SELF web are subjected to normal use. ASELF web of the present invention is comprised of a strainable networkof contiguous, “distinct”, and “dissimilar” regions, wherein thestrainable network includes at least a first region and a second region,where the first region has a “surface-pathlength” less than that of thesecond region, as measured parallel to a predetermined axis when thematerial is in an untensioned state. As used herein, the term “formedportion” refers to the portion of the material which is comprised of thedesired structure or geometry of the strainable network. As used herein,the term “surface-pathlength” refers to a measurement along thetopographic surface of the region in question in a direction parallel tothe predetermined axis. As used herein, the term “distinct” or“dissimilar” when referring to regions, refers to regions within thestrainable network having measurably different surface-pathlengths asmeasured parallel to a predetermined axis while the SELF web is in anuntensioned condition. The method for determining the surface-pathlengthof the respective regions can be found in the test methods section setforth in subsequent portions of the specification.

[0084] Methods for forming materials include, but are not limited to,embossing by mating plates or rolls, thermoforming, high pressurehydraulic forming, or casting. While in embodiments as are shown inFIGS. 5 and 5A the entire SELF web has been formed, the presentinvention may also be practiced by forming only a portion thereof.

[0085] In the preferred embodiment shown in FIGS. 5 and 5A, the firstregions 64 are substantially planar. That is, the material within thefirst region 64 is in substantially the same condition before and afterthe formation step undergone by the SELF web 52. The second regions 66include a plurality of rib-like elements 74. The rib-like elements maybe embossed, debossed or a combination thereof.

[0086] The rib-like elements 74 have a first or major axis 76 which issubstantially parallel to the second axis of the SELF web and a secondor minor axis 77 which is substantially parallel to the first axis ofthe SELF web 52. The first axis 76 of the rib-like elements 74 is atleast equal to, and preferably longer than the second axis 77. Toenhance the two-stage resistive force versus elongation behaviorcharacteristics of the panels of the diaper of the present invention,the ratio of the first axis 76 to the second axis 77 is at least 1:1,preferably at least 2:1, or greater. In general, the greater this ratio,the more pronounced will be the two-stage resistive force versuselongation characteristic of the SELF web.

[0087] The first region 64 and the second region 66 each have a“projected pathlength”. As used herein, the term “projected pathlength”refers to the length of a shadow of a region that would be thrown byparallel light. The projected pathlength of the first region 64 and theprojected pathlength of the second region 66 are equal to one another.

[0088] The first region 64 has a surface-pathlength, L1, less than thesurface-pathlength, L2, of the second region 66 as measuredtopographically in a direction parallel to the first axis of the SELFweb while the SELF web is in an untensioned condition. To enhance thetwo-stage resistive force versus elongation behavior characteristic ofthe SELF web having strainable networks of the present invention, thesurface-pathlength of the second region 66 is at least about 15 percentgreater than that of the first region, more preferably at least about 30percent greater than that of the first region, and most preferably atleast about 70 percent greater than that of the first region. Ingeneral, the greater the surface-pathlength of the second region, thegreater will be the elongation of the SELF web.

[0089] What makes the SELF web particularly well suited for use as thepanels of the diaper, and particularly the extensible back waist feature32, is that it exhibits a modified “Poisson lateral contraction effect”substantially less than that of an otherwise identical base web ofsimilar material composition. As used herein, the term “Poisson lateralcontraction effect” describes the lateral contraction behavior of amaterial which is being subjected to an applied elongation. The methodfor determining the Poisson lateral contraction effect of a material canbe found in the test methods section set forth in subsequent portions ofthe specification. Preferably, the Poisson lateral contraction effect ofthe SELF web of the present invention is less than about 0.4 when theweb is subjected to about 20 percent elongation. Preferably, the SELFweb exhibits a Poisson lateral contraction effect less than about 0.4when the SELF web is subjected to about 40, 50 or even 60 percentelongation. More preferably, the Poisson lateral contraction effect isless than about 0.3 when the SELF web is subjected to 20, 40, 50 or 60percent elongation, The Poisson lateral contraction effect of SELF websof the present invention is determined by the amount of the web materialwhich is occupied by the first and second regions, respectively. As thearea of the SELF web occupied by the first region increases, the Poissonlateral contraction effect also increases. Conversely, as the area ofthe SELF web occupied by the second region increases the Poisson lateralcontraction effect decreases. Preferably, the percent area of the SELFweb occupied by the first areas is from about 2% to about 90%, and morepreferably from about 5% to about 50%.

[0090] Web materials of the prior art which have at least one layer ofelastomeric film material will generally have a large Poisson lateralcontraction effect, i.e., they will “neck down” as they elongate inresponse to an applied force. SELF web materials of the presentinvention can be designed to moderate if not substantially eliminate thePoisson lateral contraction effect of film-based elastomeric webs of theprior art.

[0091] For the SELF web 52, the direction of applied axial elongation,D, indicated by arrows 80, in FIG. 5, is substantially perpendicular tothe first axis 76 of the rib-like elements 74. As the rib-like elements74 are able to unbend or geometrically deform in a directionsubstantially perpendicular to their first axis 76, the direction ofapplied axial elongation to cause extension in the SELF web 52 is alsosubstantially perpendicular to the first axis 76 of the rib-likeelements 74.

[0092] While the direction of applied axial elongation D indicated byarrows 80 is substantially perpendicular to the first axis 76 of therib-like elements 74, an applied axial elongation having a first axiscomponent will cause the SELF web 52 to extend in the direction ofapplied axial elongation.

[0093] In FIG. 6 there is shown a graph of the resistiveforce-elongation curve 720 of a formed polymeric SELF web of the presentinvention shown in FIG. 5 along with a curve 710 for a base film ofsimilar composition. Specifically, the samples are polymeric webmaterials comprised substantially of linear low density polyethylene,approximately 0.001 inches thick, designated Sample 1401 available fromClopay of Cincinnati, Ohio. The method for generating the resistiveforce-elongation curves can be found in the test methods section setforth in subsequent portions of the specification. Referring now to theforce-elongation curve 720, there is an initial substantially linear,lower force versus elongation stage I designated 720 a, a transitionzone designated 720 b, and a substantially linear stage II designated720 c which displays substantially higher force versus elongationbehavior.

[0094] As seen in FIG. 6, a SELF web, exhibits different elongationbehavior in the two stages when subjected to an applied elongation in adirection parallel to the first axis of the SELF web. The resistiveforce to the applied elongation is significantly different between stageI (720 a) and stage II (720 c) of curve 720 as compared to curve 710which does not exhibit this behavior. As seen in FIG. 6, the SELF webexhibits different elongation behavior in the two stages when subjectedto an applied elongation in a direction parallel to the first axis ofthe SELF web. The resistive force exerted by the SELF web to the appliedelongation is significantly less in the stage I region (720 a) versusthe stage II region (720 c) of curve 720. Furthermore, the resistiveforce exerted by the SELF web to the applied elongation as depicted instage I (720 a) of curve 720 is significantly less than the resistiveforce exerted by the base web as depicted in curve 710 within the limitsof elongation of stage I. As the SELF web is subjected to furtherapplied elongation and enters stage II (720 c) the resistive forceexerted by the SELF web increases and approaches the resistive forceexerted by the base web. The resistive force to the applied elongationfor the stage I region (720 a) of the SELF web is provided by themolecular-level deformation of the first region of the SELF web and thegeometric deformation of the second region of the SELF web. This is incontrast to the resistive force to an applied elongation that isprovided by the base web depicted in curve 710 of FIG. 6, which resultsfrom molecular-level deformation of the entire web. SELF web materialsof the present invention can be designed to yield virtually anyresistive force in stage I which is less than that of the base webmaterial by adjusting the percentage of the web surface which iscomprised of the first and second regions, respectively. Theforce-elongation behavior of stage I can be controlled by adjusting thewidth, thickness, and spacing of the first region and the composition ofthe base web.

[0095] Referring now to FIG. 5B, as the SELF web is subjected to anapplied axial elongation, D, indicated by arrows 80 in FIG. 5, the firstregion 64 having the shorter surface-pathlength, L1, provides most ofthe initial resistive force, P1, as a result of molecular-leveldeformation, to the applied elongation which corresponds to stage I.While in stage I, the rib-like elements 74 in the second region 66 areexperiencing geometric deformation, or unbending and offer minimalresistance to the applied elongation. In the transition zone (720 b)between stages I and II, the rib-like elements 74 are becoming alignedwith the applied elongation. That is, the second region is exhibiting achange from geometric deformation to molecular-level deformation. Thisis the onset of a force wall. In stage II, as seen in FIG. 5C, therib-like elements 74 in the second region 66 have become substantiallyaligned with the plane of applied elongation (the second region hasreached its limit of geometric deformation) and begin to resist furtherelongation via molecular-level deformation. The second region 66 nowcontributes as a result of molecular-level deformation in stage II asecond resistive force, P2, to further elongation. The resistive forcesto elongation provide a total resistive force, PT, which is greater thanthe resistive force depicted in stage I. Accordingly, the general slopeof the force-elongation curve in stage II is significantly greater thanthe general slope of the force-elongation curve in stage I.

[0096] The resistive force P1 is substantially greater than theresistive force P2 when (L1+D) is less than L2. While (L1+D) is lessthan L2 the first region 64 provides an initial resistive force, P1,generally satisfying the equation:${P1} = \frac{\left( {{A1}*{E1}*D} \right)}{L1}$

[0097] When (L1+D) is greater than L2 the first and second regionsprovide a combined total resistive force, PT, to the applied elongation,D, generally satisfying the equation:${PT} = {\frac{\left( {{A1}*{E1}*D} \right)}{L1} + \frac{\left( {{A2}*{E2}*{{{L1} + D - {L2}}}} \right)}{L2}}$

[0098] The maximum elongation occurring while in stage I is consideredto be the “available stretch” of the SELF web. The available stretchcorresponds to the distance over which the second region experiencesgeometric deformation. The available stretch can be effectivelydetermined by inspection of the force-elongation curve 720 as shown inFIG. 6. The approximate point at which there is an inflection in thetransition zone between stage I and stage II is the percent elongationpoint of “available stretch”. The range of available stretch can bevaried from about 10% to 100% or more; this range of elongation is oftenfound to be of interest in disposable absorbent articles, and can belargely controlled by the extent to which surface-pathlength L2 in thesecond region 66 exceeds surface-pathlength L1 in the first region 64and the properties (composition) of the base film. The term availablestretch is not intended to apply a limit to the elongation which the webof the present invention may be subjected to as there are applicationswhere elongation beyond the available stretch is desirable.Significantly higher forces are required to achieve percent elongationsin the base film equivalent to those percent elongations in the SELF web52. The approximate extent of stage I can be controlled as desired byadjusting the pathlengths, L1 and L2, in an untensioned condition. Theforce-elongation behavior of stage I can be controlled by adjusting thewidth, thickness, and spacing of first region 64 and the properties ofthe base film. The curve 730 and 735 in FIG. 7 depicts the elastichysteresis behavior exhibited by the SELF web of FIG. 5. The sample isthe same as in FIG. 6 (Clopay 1401). The sample was examined for elastichysteresis behavior at an elongation of 60%. Curve 730 represents theresponse to an applied and released elongation during the first cycleand curve 735 represents the response to applied and released elongationduring the second cycle. The force relaxation during the first cycle 731and the percent set 732 are depicted in FIG. 7. Note that significantrecoverable elongation, or useful elasticity, is exhibited at relativelylow forces over multiple cycles, i.e., this means the SELF web caneasily expand and contract to a considerable degree. The method forgenerating the elastic hysteresis behavior can be found in the testmethod section in the subsequent portion of the specification.

[0099] When the SELF web is subjected to an applied elongation, the SELFweb exhibits an elastic-like behavior as it extends in the direction ofapplied elongation and retracts to its substantially untensionedcondition once the applied force is removed, unless extended beyond thepoint of yielding. The SELF web is able to undergo multiple cycles ofapplied elongation without losing its ability to substantially recover.Accordingly, the SELF web is able to return to its substantiallyuntensioned condition once the applied elongation or force is removed.

[0100] While the SELF web may be easily and reversibly extended in thedirection of applied axial elongation, in a direction substantiallyperpendicular to the first axis 76 of the rib-like elements 74, the SELFweb is not as easily extended in a direction substantially parallel tothe first axis of the rib-like elements. The formation of the rib-likeelements allows the rib-like elements to geometrically deform in adirection substantially perpendicular to the first or major axis of therib-like elements, while requiring substantially molecular-leveldeformation to extend in a direction substantially parallel to the firstaxis of the rib-like elements.

[0101] The amount of applied force required to extend the SELF web isdependent upon the composition and thickness of the base materialforming the SELF web and the width and spacing of the first regions,with narrower and more widely spaced first regions requiring lowerapplied extension forces to achieve the desired elongation for a givencomposition and thickness. The first axis 68, (i.e., the length) of theundeformed regions 64 is preferably greater than the second axis 69,(i.e., the width) with a preferred length to width ratio of about 5:1 orgreater.

[0102] The depth and number of rib-like elements 74 can also be variedto control the extension force and available stretch of the SELF web ofthe present invention. The available stretch or elongation is increasedif for a given a number of rib-like elements, the height or degree offormation imparted on the rib-like elements is increased. Similarly, theavailable stretch or elongation is increased if for a given height ordegree of formation, the number or frequency of rib-like elements isincreased.

[0103] There are several functional properties that can also becontrolled through the application of the present invention. There isthe resistive force exerted by the SELF web against an appliedelongation, and the available stretch of the SELF web material beforethe force wall is encountered. The resistive force that is exerted bythe SELF web against an applied elongation is a function of the materialcomposition and thickness and the percent of the projected surface areaof the SELF web that is occupied by the first region. The higher thepercent area coverage of the SELF web by the first region, the higherresistive force that the SELF web will exert against an appliedelongation for a given material composition and thickness. The percentcoverage of the SELF web by the first region is determined in part ifnot wholly by the width of the first region and the spacing betweenadjacent first regions.

[0104] The available stretch of the SELF web is determined by thesurface-pathlength of the second region. This is determined at least inpart by the rib-like elements spacing, rib-like element frequency, anddepth of formation of the rib-like elements as measured perpendicular tothe plane of the SELF web. In general, the greater thesurface-pathlength of the second region, the greater the availablestretch of the SELF web.

[0105] While an entire SELF web of the present invention may include astrainable network of first and second regions, the present inventionmay also be practiced by providing only specific portions of the SELFweb with a strainable network comprised of first and second regions. Forexample, as shown in FIGS. 1 and 4, only portions of the centralwaistband panel and hip panel of the extensible back waist regioncomprise the SELF web. Portions of the central waistband panel and thehip panel also comprise the base laminate as described herein.

[0106] The configuration and spacing of the first and second regions mayalso be varied to vary the characteristics of the resultant SELF web.For example, the second regions may comprise curvilinear rib-likeelements, the first regions and the second regions may be curvilinear,or the first regions may be curvilinear. The SELF web may also exhibitan elastic-like behavior along a plurality of axes by extending the axesin a radial, fan-like array to allow the SELF web to exhibit anelastic-like behavior along a plurality of axes. For example, themultiple axes may be positioned at various angles to one another such as45°, 90°, 1350, etc. In addition to the various angles of orientation,the regions themselves may be straight, curvilinear or combinationsthereof. The surface pathlengths in the second region may also provide adifference in amplitude of the rib-like elements such that the SELF webwill have different zones of available stretch. It is also possible thatthe rib-like elements can be varied between adjacent regions to providedifferent available stretches in the adjacent second regions. The widthsof the first region may also vary across the web with the narrowerregions offering a lower resistive force to an applied elongation ascompared to the higher resistive force offered by the wider firstregion.

[0107] The SELF web also need not be extensible only in the directionparallel to the lateral centerline of the diaper as is shown in FIG. 1.For example, the first axis and the second axis of the SELF web may bedisposed at an angle to the longitudinal centerline and lateralcenterline of the diaper 20, respectively. Thus, the SELF web wouldaxially elongate along a line at an angle to the lateral centerline ofthe diaper. This angle is preferably between about 00 and about 30° forthe diapers of the present invention. Further, portions of the SELF webmay have different angles of extensibility. For example, in the sidepanels, a portion of the side panel closest to the end edge of thediaper, the waist panel, may be extensible in a direction parallel tothe lateral centerline of the diaper; however, the portion of the SELFweb closest to the lateral centerline, the thigh panel, may have anextensibility nonparallel to the direction of extensibility of the waistpanel such that it is disposed at an angle to the lateral centerline.This multi-directional SELF panel can provide improved waist and legconformity.

[0108] Referring now to FIG. 8, there is shown an apparatus 400 used toform the SELF web 52 shown in FIG. 5. Apparatus 400 includes plates 401,402. Plates 401, 402 include a plurality of intermeshing teeth 403, 404,respectively. Plates 401, 402 are brought together under pressure toform the base film 406.

[0109] Referring now to FIG. 9, it can be seen that plates 401 and 402each have a first axis “l” and a second axis “t” which is substantiallyperpendicular to the first axis. Plate 401 includes toothed regions 407and grooved regions 408 both which extend substantially parallel to thefirst axis of the plate 401. Within toothed regions 407 of plate 401there are a plurality of teeth 403. Plate 402 includes teeth 404 whichmesh with teeth 403 of plate 401. When the base film 406 is formedbetween plates 401, 402 the portions of the base film 406 which arepositioned within grooved regions 408 of plate 401 and teeth 404 onplate 402 remain undeformed. These regions correspond with the firstregions 64 of the SELF web 52 shown in FIG. 5. The portions of the basefilm 406 positioned between toothed regions 407 of plate 401 and teeth404 of plate 402 are incrementally and plastically formed creatingrib-like elements 74 in the second regions 66 of the SELF web 52.

[0110] The method of formation can be accomplished in a static mode,where one discrete portion of a base film is deformed at a time. Anexample of such a method is shown in FIG. 10. A static press indicatedgenerally as 415 includes an axially moveable plate or member 420 and astationary plate 422. Plates 401 and 402 are attached to members 420 and422, respectively. While plates 401 and 402 are separated, base film 406is introduced between the plates, 401, 402. The plates are then broughttogether under a pressure indicated generally as “P”. The upper plate401 is then lifted axially away from plate 402 allowing the formed SELFweb 408 to be removed from between plates 401 and 402.

[0111]FIG. 11 is an example of a continuous, dynamic press forintermittently contacting the moving web and forming the base material406 into a formed web similar to the SELF web 52 of FIG. 5. Polymericfilm 406 is fed between plates 401 and 402 in a direction generallyindicated by arrow 430. Plate 401 is secured to a pair of rotatablymounted arms 432, 434 which travel in a clockwise direction which moveplate 401 in a clockwise motion. Plate 402 is connected to a pair ofrotary arms 436, 438 which travel in a counter clockwise directionmoving plate 402 in a counter clockwise direction. Thus, as web 406moves between plates 401 and 402 in direction indicated by arrow 430, aportion of the base film between the plates is formed and then releasedsuch that the plates 401 and 402 may come back grab and form anothersection of base film 406. This method has the benefit of allowingvirtually any pattern of any complexity to be formed in a continuousprocess, e.g., uni-directional, bi-directional, and multi-directionalpatterns.

[0112] The dynamic press of FIG. 11 could be used on a completedabsorbent article to form strainable networks into the completedproduct. For example, the entire or portions of the completed absorbentarticle could be placed between plates 401 and 402 to create astrainable network in all layers of the absorbent article.

[0113] Another method of forming the base material into a SELF web isvacuum forming. An example of a vacuum forming method is disclosed incommonly assigned U.S. Pat. No. 4,342,314, issued to Radel et al. onAug. 3, 1982. Alternatively, the SELF web of the present invention maybe hydraulically formed in accordance with the teachings of commonlyassigned U.S. Pat. No. 4,609,518 issued to Curro et al. on Sep. 2, 1986.Each of the above patents are being incorporated herein by reference.

[0114] In FIG. 12 there is shown another apparatus generally indicatedas 500 for forming the base film into a formed SELF web. Apparatus 500includes a pair of rolls 502, 504. Roll 502 includes a plurality oftoothed regions 506 and a plurality of grooved regions 508 that extendsubstantially parallel to an axis running through the center of thecylindrical roll 502. Toothed regions 506 include a plurality of teeth507. Roll 504 includes a plurality of teeth 510 which mesh with teeth507 on roll 502. As a base polymeric film is passed between intermeshingrolls 502 and 504, the grooved regions 508 will leave portions of thefilm unformed producing the first regions 64 of the SELF web 52. Theportions of the film passing between toothed regions 506 and teeth 510will be formed by teeth 507 and 510; respectively, producing rib-likeelements 74 in the second regions 66 of the SELF web 52.

[0115] Alternatively, roll 504 may consist of a soft rubber. As the basefilm is passed between toothed roll 502 and rubber roll 504 the film ismechanically formed into the pattern provided by the toothed roll 502.The film within the grooved regions 508 will remain unformed, while thefilm within the toothed regions 506 will be formed producing rib-likeelements of the second region.

[0116] Referring now to FIG. 13, there is shown an alternative apparatusgenerally indicated as 550 for forming the base film into a SELF web inaccordance with the teachings of the present invention. Apparatus 550includes a pair of rolls 552, 554. Rolls 552 and 554 each have aplurality of toothed regions 556 and grooved regions 558 extending aboutthe circumference of rolls 552, 554 respectively. As the base filmpasses between rolls 552 and 554, the grooved regions 558 will leaveportions of the film unformed, while the portions of the film passingbetween toothed regions 556 will be formed producing rib-like elements74 in second regions 66.

[0117] While the SELF web has been described as a single base layer ofsubstantially planar polymeric film, the present invention may bepracticed equally well with other base materials or with laminates ofmaterials. Examples of base materials from which the SELF web of thepresent invention can be made include two-dimensional apertured filmsand macroscopically expanded, three-dimensional, apertured formed films.Examples of macroscopically expanded, three-dimensional, aperturedformed films are described in U.S. Pat. No. 3,929,135 issued to Thompsonon Dec. 30, 1975; U.S. Pat. No. 4,324,246 issued to Mullane, et al. onApr. 13, 1982; U.S. Pat. No. 4,342,314 issued to Radel, et al. on Aug.3, 1982; U.S. Pat. No. 4,463,045 issued to Ahr, et al. on Jul. 31, 1984;and U.S. Pat. No. 5,006,394 issued to Baird on Apr. 9, 1991. Each ofthese patents are incorporated herein by reference. Examples of othersuitable base materials include composite structures or laminates ofpolymer films, nonwovens, and polymer films and nonwovens. The laminatesof polymer films and nonwovens may also comprise absorbent or fibrousabsorbent materials, foams, or other compositions. Additionalreinforcing elements can also be added for strength and recoverybenefits.

[0118] Base materials comprising laminates of apertured films andnonwoven materials may also be used whereby in the process of formingsuch materials, the connections between a plurality of the nonwovenfibers are broken up to protrude slightly through the apertures of theapertured film.

[0119] It may be desirable in certain embodiments to have the SELF webexhibit a certain degree of bulkiness. Laminates of polymer films withhigh-loft nonwoven materials, and laminates with multi-layers ofnonwovens are ways of providing increased bulk. Other methods forcreating bulk include the formation of a single layer of polymer film inthe manner of this invention followed by prestretching of the film andsubsequent application of the nonwoven to one or both sides while thepolymer film is in its prestretched condition. Upon relaxation of thestretch, the nonwoven material forms puckers which give the materialadded bulk. Another method for making bulky laminates is by formingindividual polymeric film layers in the manner of this invention,followed by lamination of multiple layers of these materials. Threedimensionally apertured films that have been formed using the methoddescribed herein also provide good bulk in a laminate structure.

[0120] Other materials which may be subject to the deformation processesdisclosed herein for producing webs which exhibit an elastic-likebehavior in the direction of applied force include polymeric foams andthermally bonded air-laid fibrous structures.

[0121]FIG. 14 shows the force elongation behavior for a base web 830 andthe formed SELF web 840 of the present invention wherein both webs arecomprised of a laminate of a layer of the Clopay 1401 polyethylene blendfilm of FIG. 6 adhered via hot melt glue available from FindleyAdhesives, of Wauwautosa, Wis., Sample 2301, to a layer of nonwovenmaterial made substantially of polypropylene fibers as is available fromVeratec of Walpole, Mass., under the designation P-11. Referring now tocurve 840, there is an initial substantially linear, lowerforce-elongation stage I designated 840A, a transition zone designated840B, and substantially linear stage II designated 840C. For thislaminate web, note the distinctive lower force 2-stage behavior of theformed SELF web as compared to the base web. The curves 850 and 855 inFIG. 15 show the hysteresis behavior of the same type when examined at60% elongation. Curve 850 represents the response to applied elongationduring the first cycle and curve 855 represents the response to appliedelongation during the second cycle. The force elongation during thefirst cycle 851 and the percent set 852 are depicted in FIG. 15. Notethat this laminate web exhibits a very significant elastic recovery overthe observed range of elongation.

[0122] In a preferred embodiment of the present invention, the SELF webcomprises a laminate of two layers comprising an inner layer 53 and anouter layer 55. The inner layer 53 is preferably a nonwoven materialsuch as the P-8 material previously described. The outer layer 55 ispreferably the base polymeric film as described herein with reference toFIG. 5 (Clopay 1401) or the backsheet (Tredegar P8863). Alternatively, asupport layer may be added to provide a three layer laminate. Further, anonwoven layer may be added over the outer layer to provide a softerfeel for the outside of the waist feature. The laminates may be combinedby any of a number of bonding methods known to those skilled in the art.Such bonding methods include but are not limited to thermal bonding;adhesive bonding (using any of a number of adhesives including but notlimited to spray adhesives, hot melt adhesives, latex based adhesivesand the like); sonic bonding; and extrusion laminating whereby apolymeric film is cast directly onto a nonwoven substrate, and whilestill in a partially molten state, bonds to one side of the nonwoven orwhere a meltblown nonwoven is directly attached to a polymeric web.

[0123]FIG. 4 shows a blown up plan view of the diaper of the presentinvention showing the specific design of the SELF webs forming thediaper and the relative positioning of each of the panels and otherelements forming the diaper. As discussed hereinabove, the width(longitudinal dimension in FIG. 1) of the bands (the channels or firstregions) of the SELF web is used to control the extension forces and theavailable stretch of the resultant SELF web. In the preferred embodimentshown in FIG. 4, the central waistband panel 34 has four bands 64′ of 3mm width each. There are also three pleats 66′ spaced at a width of 6.35mm. Thus, the central waistband panel has an extension force at 50%extension of about 17 g/cm. The available stretch of the centralwaistband panel is about 60%. The preferred side panels 36 comprise aSELF web having an equal to or lower extension force and higheravailable stretch than the central waistband panel 34. The side panels36 each preferably comprise seven bands 64′″ of 3 mm width and sixpleats 66′″ spaced at a width of 5.6 mm. The side panels thus each havea force/extension characteristic at a 50% extension of about 13 g/cm.The available stretch of each side panel is about 110%. The side panelshave different force/extension properties from the central waistbandpanel, despite the fact that the bands are the same, due to thedifference in properties of the base materials and the width of thepleats. (One of the layers of the side panel is the Clopay 1401polyethylene film while the one of the layers of the central waistbandpanel is the Tredegar P8863 polyethylene film.) The hip panel 38comprises a SELF web designed to provide seven bands 64″ of 1 mm widthand eight pleats 66″ of 6.35 mm width. The hip panel thus has anextension force at 50% extension of about 3 g/cm. The available stretchof the hip panel is about 60%. Thus, the hip panels preferably haveforce/extension properties less than the side panels and less than thecentral waistband panel; however, the amount of extension of the hipspanel is greater than the central waistband panel. The extension forcesof the hip panel are less than that of the central waistband panel dueto the width of the bands.

[0124] With the force/extension characteristics providing extension asdescribed above, it has also been found that the positional relationshipbetween certain elements of the extensible back waist feature and/or thediaper further enhance the fit and containment of the diaper.

[0125] It has been found that the side panels 36 should be joined to notonly the central waistband panel 34 but also to at least a portion ofthe hip panel 38. This configuration allows forces generated in the sidepanels by fitting the diaper on the wearer to be transmitted not onlythrough the central waistband panel but also the portion of the hippanel adjacent the central waistband panel, The hip panel thus extendsto accommodate forces distributed in the central waistband panel causingless strain and stress on the diaper and expands with the forces in theside panels to better accommodate the hips and buttocks of the wearerwhile providing additional extensibility to accommodate furthermovements of the hips and buttocks as the wearer moves, walks, stands,etc. While the side panels may be disposed so as to be longitudinallyaligned with the entire hip panel, it is preferred that the side panelsare longitudinally aligned with only a portion of the hip panel so thata continuous line of force through the waistband is provided and inorder to maximize expansion of the lower back side of the hip panel. Itis preferred that the side panel overlap with the hip panels from 10% toabout 90%, more preferably from about 40% to about 60% of the length(longitudinal dimension) of the total length of the side panel. In theembodiment shown in FIG. 1, the side panels overlap with the hip panelabout 27 mm with the hip panels extending beyond the side panels fromabout 13 mm to about 43 mm, preferably about 28 mm.

[0126] As shown in FIG. 4, the side panel 36 is preferably joined to anonextensible portion of both the central waistband panel 34 and the hippanel 38. This nonextensible portion, bridging element 58, allows forcesgenerated in the side panels 36 during application and use of the diaperto be “diffused” or spread out to more evenly distribute the forces inthe central waistband panel 34 and the hip panel 38. While the sidepanel 36 could be joined to an extensible portion or be constructed asunitary with the SELF webs of the central waistband panel and the hippanel, such a construction allows direct force transfer through specificsites thereby concentrating the forces and stresses rather than allowingthem to be distributed over a wider area. The side panels can be joinedto the panels, preferably the bridging element 58, in a number ofdifferent ways as are known in the art and previously discussed herein,including by adhesives, heat/pressure bonds ultrasonic bonding ormechanical bonding. The side panels are preferably bonded to the otherpanels via mechanical bonding.

[0127] It has also been found that the positioning of the operative ends55 of the leg elastics (elastic strands 54) with respect to the leg edge37 of the side panel 36 is an important parameter in optimizing fitabout the leg of the wearer. While the elastic strands 54 may be anylength consistent with providing a leg cuff, it has been found that theoperative ends 55 of the elastic strands 54 preferably extend to the legedge 37 of the side panels 36 to eliminate the possibility of leggapping and the resultant leakage at the back of the legs. (The term,“operative ends”, as used herein means the point where the elasticstrand is operatively joined to the leg flap panel and contracts orgathers the leg flap panel. Thus, unadhered segments of the elasticstrands may extend beyond the zones defined herein since they do not acton the diaper or perform a contractive or gathering function.) Leakageand gapping at the back of the legs is improved when the elastic strands54 extend beyond the waist edge 56 of the absorbent core 28 into the hippanel 38 because the elastic strands tend to curve with the extension ofthe hip panel and better fit around the buttocks of the wearer. (SeeFIG. 3.) The position of the operative ends 55 of the elastic strands 54in the hip panel 38 also couples the leg closure and leg fit with thecentral waistband panel 34 and side panels 36 to provide a continuousclosure and line of force about the legs. Thus, it has been found thatthe operative ends of the elastic strands should extend to at least thehip panels, preferably into the hip panels, and more preferably to aboutthe leg edge of the side panels, most preferably within about 10 mm ineither direction from the leg edge.

[0128] The positioning of the absorbent core 28 may also affect theperformance of the diaper and the back waist feature. Since theabsorbent core is relatively nonextensible, positioning the absorbentcore in an extensible feature can degrade the integrity of the coreduring use, especially when wet, and can restrict the extension of thepanel. Thus, as shown in FIG. 1, the absorbent core 28 does not extendinto the hip panel 38. However, the absorbent core may extend into thehip panel if more absorbent capacity is needed or a stiffener isrequired. If the absorbent core extends into the hip panel, it ispreferable to either not make that portion of the hip panel extensibleor not join that portion of the absorbent core to the extensible panel,thus allowing the absorbent core to “float” and not restrict theextension of the hip panel.

[0129]FIG. 3 shows the diaper of FIG. 1 in a flat configurationapproximating the forces applied to the extensible back waist feature 32during wear. As can be seen from the drawing, the side panels 36 extendsuch that their waist edge 37′ is extended more than the leg edge 37(about 80 mm versus 75 mm) such that more of the forces through the sidepanels are resolved adjacent the waist edge 379 (the end edge 48 of thediaper 20). The central waistband panel 34 has also been extended (toabout 250 mm) with the majority of the forces resolved through thecentral waistband panel. The hip panel 38 has been extended with moreextension adjacent its upper edge than its lower edge. However, thisextension allows the hip panel to better wrap the hips and buttocks ofthe wearer resulting in better fit and improved containment at the hips.The elastic strands 54 of the leg cuffs 30 are shown to curve in the hippanels 38 to provide a cuff that better conforms to the buttocks of thewearer. (It should be noted that if the leg cuff comprises a barriercuff as is described in the above-referenced U.S. Pat. No. 4,695,278(Lawson), the barrier cuff will also curve in the same manner andprovide better fit about the buttocks.)

[0130] As shown in FIG. 1, the diaper 20 may also be provided with anextensible front waist feature 42. The extensible front waist feature 42is designed to fit around the abdomen in the front waist of the wearerto improve the fit and containment of the diaper at the front waist. Theextensible front waist feature 42 is positioned in the front waist panel43 and extends longitudinally outwardly from the chassis assembly 22,preferably the waist edge 56 of the absorbent core 28, and generallyforms at least a portion of the end edge 48 of the diaper 20 in thefront waist region 45. The extensible front waist feature 42 maycomprise any of the known configurations of an elastic feature or any ofthe extensible features as described herein. For example, the extensiblefront waist feature may comprise any of the elasticized waistbands asare known in the art such as are disclosed in the above-referenced U.S.Pat. No. 4,515,595 (Kievit, et al.) and U.S. Pat. No. 5,151,092 (Buell,et al.). Further, the extensible front waist feature may comprise astretch laminate such as a zero strain stretch laminate as is describedin U.S. Pat. No. 5,151,092 (Buell, et al.). Examples of alternativeextensible front waist features are described herein with respect to thealternative embodiments. In an especially preferred embodiment of thepresent invention as is shown in FIG. 1, the front waist panel 43comprises a SELF web. The SELF web of the front waist panel preferablyhas the same or similar force/extension characteristics as the SELF webof any of the other panels of the diaper, including, for example, thecentral waistband panel, the hip panel, or the side panel. However, theSELF web of the front waist panel may also be designed to have its ownunique force/extension characteristics. In a preferred embodiment for alarge (8 kg to 14 kg) baby diaper, the front waist panel has alongitudinal dimension of about 15 mm and a lateral dimension of about180 mm. The extension force of the front waist panel is preferablygreater than or equal to the extension force of the central waistbandpanel. The SELF web of the front waist panel is preferably designed tohave three bands of 3 mm width and 2 pleats of 6.35 mm width to providean extension force at 50% extension of 26 g/cm with an available stretchof 60%.

[0131] The diaper 20 is also provided with a closure system for fittingthe diaper on the wearer. While the closure system may take on a numberof configurations such as adhesive tape tabs, mechanical closure tapetabs, fixed position fasteners, side seams as for training pants, or anyother closure means as are known in the art; as shown in FIG. 1, theclosure system preferably comprises an adhesive tape tab fasteningsystem including a pair of tape tabs 40 and a landing member, preferablya reinforcing strip 41 as in FIG. 1 or, the alternative, a portion ofthe backsheet, positioned in the front waist region 45 of the diaper 20.Examples of suitable adhesive tape tab fastening systems are disclosedin U.S. Pat. No. 3,848,594 issued to Buell on Nov. 19, 1974; and U.S.Pat. No. 4,662,875 issued to Hirotsu and Robertson on May 5, 1987; eachof which are incorporated herein by reference. Examples of other closuresystems, including mechanical closure systems, useful in the presentinvention, are disclosed in U.S. Pat. No. 4,869,724 issued to Scripps onSep. 26, 1989; U.S. Pat. No. 4,848,815 issued to Scripps on Jul. 11,1989; and the two-point fastening system described in U.S. Pat. No.5,242,436 issued to Weil, Buell, Clear, and Falcone on Sep. 7, 1993;each of which are incorporated herein by reference. When a two-pointfastening system is used, the waist closure members of the waist closuresystem are preferably longitudinally aligned with the extensible frontwaist feature and laterally aligned with the elastic strands of theextensible leg cuff to provide an effective closure about both the legsand the waist.

[0132] In an alternative embodiment of the present invention, the diapermay also be provided with ear flap panels that extend laterallyoutwardly from the chassis assembly and the front waist panel. The earflap panels provide a structure to which the waist feature can beattached to encircle the legs and waist of the wearer. The ear flappanels may take on a number of different sizes, shapes, configurations,and materials. The ear flap panels may comprise a portion of thematerial(s) making up one or more of the diaper elements, including thetopsheet and the backsheet. Alternatively, the ear flap panels maycomprise a separate element or a plurality of elements affixed to thediaper. Suitable materials for use as the ear flap panels include wovenwebs; nonwoven webs; films, including polymeric films; foams; laminatematerials including film laminates, nonwoven laminates, or zero strainlaminates; elastomers; composites; SELF webs; or any combination ofthese materials. The ear flap panels may be joined to the chassisassembly by any means as are known in the art; for example, the earflaps may be continuously or intermittently bonded to the chassisassembly using heated or unheated adhesive, heat bonding, pressurebonding, ultrasonic bonding, dynamic mechanical bonding, or any othermethod that is known in the art.

[0133] The diaper 20 is preferably applied to a wearer by postioning theback waist region 46 under the wearer's back and drawing the remainderof the diaper between the wearer's legs so that the front waist region45 is positioned across the front of the wearer. The tab portions of thetape tabs 40 are then released from the release portion. The diapererthen wraps the side panel 36 around the wearer, while still grasping thetab portion. The side panel will typically be extended and tensionedduring this operation so as to conform to the size and shape of thewearer. The tape tab 40 is secured to the reinforcing strip 41, thelanding member, on the chassis assembly 22 to effect a side closure. Theprocess is then repeated with the other tape tab. Thus, the diaper isclosed on the wearer and the extensible back waist feature and the otherelements, if provided, provide the fit and containment benefits asdescribed herein.

[0134] Alternatively, the diaper may be provided with a closure systemthat allows the side panels to be first joined together. The diapererthen brings the chassis assembly between the legs of the wearer andjoins the chassis assembly to the outer layer of the waist feature. Sucha configuration and securing method is more fully described in theabove-referenced U.S. application Ser. No. 08/044,562 (New, et al.).

[0135]FIG. 16 is a simplified plan view of an alternative disposablediaper 1620 of the present invention wherein the hip panel 1638 has amultiple zone SELF web construction. (The particular construction of theSELF web has been simplified by showing the bands making up the SELFweb.) The hip panel 1638 has three zones: a central zone 1600 and twoleg zones 1602. The SELF web of each leg zone 1602 preferably has thefirst and second regions disposed at an angle to the lateral directionso that extensibility is provided at an angle to the lateral direction.Lateral forces developed in the side panels 36 are directed along a lineat an angle to the lateral direction through the hip panels 1638 to moreconformably fit about the buttocks of the wearer. The SELF web of thecentral zone 1600 is similar to the SELF web pattern of the hip panel 38shown in FIG. 1. The central zone 1600 provides lateral extensibilityadjacent the central waistband panel 34. In the embodiment shown in FIG.16, the central zone 1600 has a higher extension force than the legzones 1602 (lower extension/available stretch), preferably even highthan the central waistband panel 34, to provide snug fit by holding thediaper in place without roll-over or “pooching” out. The central zone1600 may even provide no extensibility (i.e., nonextensible), ifdesired,

[0136] It is preferred, however, in some embodiments, that the extensionforces of the central zone be less than or equal to the lateral vectorcomponent of the extension forces of the leg zones, particularly when abarrier cuff is used for the leg cuff.) This configuration of the hippanel better distributes forces in both the legs and the buttocks regionby allowing extensibility both in the lateral and longitudinal directionin the leg zone. When the leg cuff of the diaper comprises a barriercuff such as is described in U.S. Pat. No. 4,695,278 (Lawson), the hippanel may also comprise a central zone and a pair of leg zones. The sideedges of the central zone are positioned inward from the proximal edgesof the barrier cuffs. Such a proximal edge is positioned in each legzone. The extension force of the central zone is preferably less thanthe extension force of the leg zone to anchor each barrier cuff whileproviding extensibility for the hip panel.

[0137]FIG. 17 shows an alternative embodiment of a side panel 1736 ofthe back waist feature 32 wherein the side panel 1736 has a multiplezone SELF web construction. The portion of the side panel 1736 adjacentthe end edge 48 of the diaper and in alignment with the centralwaistband panel 34, the waist zone 1700, comprises a first SELF web thatprovides distribution of the extension forces and extension in a firstdirection having a vector component in the lateral direction, preferablythe lateral direction. The side panels 1736 also have a leg zone 1702adjacent the leg edge 37 of the side panel 1736 that comprises a secondSELF web having a pattern of bands and pleats providing force resolutionand extensibility in a second direction different from the firstdirection, preferably at an angle to the lateral direction. This seconddirection of extension provides better fit about the wearer bydistributing the forces at an angle in the leg zone 1702. It should alsobe noted that while the embodiment of FIG. 17 shows the side panel asone continuous member, the side panel can also be constructed from twoseparate SELF webs joined together to form a two by two side panel suchas is disclosed in the above-referenced U.S. patent application Ser. No.08/155,048 (Robles, et al.), hereby incorporated herein by reference.

[0138]FIG. 18 shows an alternative disposable diaper 1820 of the presentinvention wherein the leg flap panels 1831 further comprise a SELF weband the front waistband panel 1842 is a multiple zone SELF web. The SELFweb of the leg flap panels provides extensibility in the lateraldirection. By providing a SELF web leg cuff next to, over, or outside ofthe elastic strands 54, the diaper 1820 has an area adjacent the legswhich can expand when needed for additional void volume due to heavyloading, and also to provide a snug fit to reduce the possibility ofleakage in the leg regions due to gapping. As the diaper is loaded andgets heavier, the weight forces cause the extensible leg flap panels1831 to expand in the lateral direction thereby reducing gapping at thelegs due to this expansion instead of the cuff being pulled downward bythe weight and gapping away from the leg. The result is that action ofthe leg cuff 30 is independent from the absorbent core 28 thus providingbetter fit and containment. Additionally, the SELF web enhances thesoftness of the product in the leg cuff and contributes to overall babyfriendly aesthetics. In fact, the entire diaper, including the chassispanel 22, may, if desired, comprise a SELF web to provide softness andcontainment characteristics. In the embodiment shown in FIG. 18, theSELF web of the leg flap panels 1831 has 75 bands of 1 mm width and 74pleats of 6.35 mm width each. The leg flap panel thus has an extensionforce at 50% extension of 6 g/cm and an available stretch of 60%. Theelastic strands 54 are operatively joined in the leg flap panel toprovide an extension force of 60 g at 85% extension. (It has been foundthat the SELF web should preferably have an extension force no greaterthan ½ of, preferably between about ⅕ to about {fraction (1/10)} of, theextension force of the elastic strands 54. Since the elastic strands 54are preferably operatively joined to the leg flap panel 1831 to providean extension force between about 50 and about 60 g, then the extensionforces of the leg flap panels are preferably less than 30 g/cm, morepreferably less than 20 g/cm, and most preferably less than 10 g/cm, at50% extension. These extension force characteristics provide theimprovements in gapping and containment described herein.

[0139] The front waist panel 1832 has multiple zones: a centralwaistband zone 1800 and a tummy zone 1802. The central waistband zone1800 provides the function of the front waist feature as previouslydescribed herein. The tummy zone 1802 provides extension about the bellyof the wearer which typically expands and contracts during use. Thus,the tummy zone 1802 moves with the stomach of the wearer and reduces thetendency of the front waist to sag and gap during use. The extensionforces of the overall front waist panel 1843 are preferably less thanthe extension force of the central waistband panel 34 of the back waistfeature 32 to allow the front to “flair” out. The extension force of thefront waist panel 1843 is preferably between about 5 g/cm and 15 g/cm at50% extension. In an alternative embodiment, the extension force of thetummy zone 1802 may be less than or equal to the extension force of thecentral waistband zone 1800 to allow more extension in the tummy panelto accommodate the wearer's stomach and to provide a line of tension inthe central waistband zone that more snugly fits the wearer. (in analternative embodiment, this diaper may also be provided with the twopoint fastening system described in U.S. Pat. No. 5,242,436 (Weil, etal.) to further enhance the fit of the diaper.) FIG. 19 shows the diaperof FIG. 18 in a flat configuration approximating the forces appliedduring wear. As can be seen from the drawing, the extensible back waistfeature 32 extends in the same manner as described with respect to FIG.3. However, due to the extensibility of the leg flap panels 1831 and thegreater extensibility of the front waist panel 1843, the front waistregion of the diaper also tends to flare out. Thus, the diaper 1820provides an hourglass shape-type fit without the added and the wastedmaterial required for an hourglass shaped diaper. The elastic strands 54of the leg cuffs 30 are shown to curve in the front waist to provide acuff that better conforms to the upper thighs of the wearer. In effect,curved elasticization is achieved with a rectangular diaper. (It shouldbe noted that if the leg cuff comprises a barrier cuff as is describedin the above-referenced U.S. Pat. No. 4,695,278 (Lawson), the barriercuff will also curve and provide better fit.)

[0140]FIG. 20 shows an alternative embodiment of a diaper 2020 of thepresent invention. The diaper 2020 has a generally hourglass shaperather than the T-shape previously discussed. The hourglass shape has aleg cutout in the crotch region of the diaper to provide fit about thelegs. The extensible back waist feature 32 is similar to the extensibleback waist feature described with respect to the T-diaper except for theshape of each panel. Further, in this embodiment, the absorbent core 28extends into a portion of the hip panel 38. In an especially preferredembodiment, the absorbent core 28 is not joined to the hip panel 38 suchthat it is allowed to “float” in the hip panel 38. The absorbent corethus provides stiffness in a portion of the hip panel to preventbunching of the hip panel. The extensible front waist feature 2042preferably has a pentagon shape such as is described in U.S. Pat. No.5,151,092 (Buell, et al.). In the embodiment shown in FIG. 20, theextensible front waist feature 2042 comprises a SELF web of the presentinvention wherein the extensibility of the SELF web is in a pentagonshape due to the nonextensible chevron-shaped landing member,reinforcing strip 2041, being joined over a portion of the SELF web. Theclosure system for the diaper is preferably the dual tension fasteningsystem described hereinafter providing an angled line of tension aboutthe wearer. The dual tension fastening system comprise a primaryfastening system and preferably a waist closure system. As shown in FIG.20, the tape tabs 2040 of the primary fastening system are disposed atan angle to the lateral direction to provide such an angled line offastening. The diaper 2020 is also provided with a waist closure systemincluding a pair of first attachment components 2002 longitudinallyaligned with the extensible front waist feature 2042 to provide tensionthrough the extensible front waist feature and a second attachmentcomponent (not shown) comprising a portion of the topsheet 24.

[0141] The closure system anchors the diaper about the wearer throughoutthe diapers use so the diaper has a reduced likelihood to sag/gap andslide/slip during use. The closure system is designed to create a lineor zone of tension causing a hoop force connecting the lumbar curve ofthe back over the hips to under the abdominal crease to form theanchoring function. This line or lines (zone) of tension (hereinafter,the primary line of tension) is disposed substantially about theperimeter of the low motion zone of the wearer to impart anchoringforces that maintain the position of the diaper throughout wearing. Theprimary line of tension is preferably disposed at an angle to thehorizontal on the body of the wearer (at an angle to the lateraldirection of the diaper) such that the primary line of tension extendsfrom around the lumbar curve (the small of the back) over the iliaccrest of the hips to the front of the wearer, preferably below the lineof the abdominal crease. Thus, the primary line of tension is disposedin the zone of minimal changing body dimension, a sustained wearingposition (i.e., the primary line of tension is not disposed over theabdomen of the gluteus maximus which increase and decrease in dimensionduring movement), such that the primary line of tension stabilizes andmaintains anchoring forces which maintaining the position of the diaperon the wearer such that diaper is unlikely to slide or slip downwardduring the entire time of use due to the movement of the wearer or tothe force of the increased weight of the diaper when it is loaded. Theangled primary line of tension created by the closure system alsoimparts an upward anchoring force on the diaper tending to pull thediaper up on the body, and thus counteract the weight force of theloaded diaper, since the primary line of tension has a vector componentin the longitudinal direction. The normal anchoring force is created bythe primary line of tension (another vector component of the angledprimary line of tension) anchoring the diaper, particularly theabsorbent core, in the low motion zone since the normal anchoring forcesact compressively to push the absorbent core toward the body. Thesenormal anchoring forces thus assist in maintaining the fit of the diaperas well as reducing leakage since the absorbent core is maintained inclose relationship with the body. The angled primary line of tensionalso tends to reduce red marking since the anchoring forces are disposedin the low motion zone such that the body dimension is not increasing ordecreasing along the primary line of tension which could cause redmarking.

[0142] Since the primary line of tension is to be disposed at an angleto the lateral direction to provide its anchoring function, the closuresystem is designed to provide an angled closure mechanism to insure sucha primary line of tension is imparted to the diaper. The closure systemmay thus comprise a number of different fastening systems for providingan angled primary line of tension. For example, the closure system maysimply comprise a primary fastening system. The closure system mayadditionally anchor a portion of the extensible front waist feature,and, if desired, a portion of the leg cuff.

[0143] For the closure system shown in FIG. 20, each securement memberof the closure system preferably comprises a tape tab 2040 capable ofbeing secured to a landing member, preferably reinforcing strip 2041, soas to provide a primary line of tension through the diaper at an angleto the lateral direction. Thus, the tape tab is generally shaped andoriented to allow the tape tab to engage the landing member so as toprovide a primary line of tension at an angle to the lateral direction,preferably through the diaper substantially about the low motion zone.In the embodiment shown in FIG. 20, the tape tab 2040 is joined to theside panel 36 at an angle to the lateral direction to provide the angledprimary tension line desired. For example, a rectangular tape tab suchas known in the art or a tape tab having any other shape may be rotatedwith respect to the lateral direction when applied to the diaper suchthat the tape tab is disposed at an angle to the lateral direction ofpreferably between about 5° to about 30°, preferably from about 15° toabout 20°.

[0144] An alternative embodiment of the tape tab may have the tabportion shaped and oriented at an angle to the lateral direction toinsure the formation of the primary line of tension at an angle to thelateral direction. Most preferably, the sidelong edges of the tape tabsare curved to allow angled taping in order to follow the shape/build ofthe wearer, to create the angled primary line of tension about the lowmotion zone to anchor the diaper on the wearer, and to allow thediaperer to conveniently apply the tab portion on the landing member soas to accommodate the diaper design. Further, the curved shape of thesidelong edges of the tab portion allows high tape placement in the backwaist region yet allows low tape placement on the landing member tominimize marking of the stomach, hips and legs of the wearer to improvethe comfort of the diaper for the wearer. The tab portion alsoaccommodates the leg of the wearer in that if the tape tab waspositioned too low on the product, marking could occur on the legs ofthe wearer which would negatively impact comfort and fit. An example ofsuch a tape tab design is disclosed in U.S. patent application Ser. No.08/072,300, “Absorbent Articles Providing Sustained Dynamic Fit” filedby LaVon, et al. on Jun. 3, 1993, which patent application isincorporated herein by reference.

[0145] The landing member can also assume varying sizes and shapes toprovide the angled primary line of tension. In a preferred embodiment asillustrated in FIG. 20, the landing member comprises a reinforcing strip2041 having a chevron shape so as to create the angled primary line oftension of the present invention. The reinforcing strip 2041 is alsopreferably provided with indicia means 2004 for aiding the diaper andfitting the diaper to a wearer to obtain optimal waist fit and legopening fit. The indicia means 2004 are preferably disposed in rowsdisposed at an angle to the lateral direction, preferably at the sameangle as the tape tabs 2040, to allow angled fastening of the tape tabfor optimized fit and for providing an angled primary line of tension.(In an alternative configuration, the landing member can be extensible,for example—formed from a SELF web comprising a nonwoven material, toallow the front waist region to expand even more to accommodate thegrowth of the wearer's stomach.)

[0146] As shown in FIG. 20, the closure system preferably additionallycomprises a waist closure system that anchors a span of the front waistpanel 43, preferably the extensible front waist feature 2042. Such awaist closure system is disclosed in the above-referenced U.S. patentapplication Ser. No. 08/072,300 (LaVon, et al.) and U.S. Pat. No.5,242,436 (Weil, et al.). Alternatively, the components of the waistclosure system can also be configured to provide an angled line oftension (e.g., the first attachment components may be joined at an angleto the lateral direction).

[0147]FIG. 21 shows a further alternative embodiment of an extensiblefront waist feature 2142 of the present invention. The front waist panel2143 has a central waistband panel 2100 and a pair of ear panels 2102disposed on either lateral side of the central waistband panel 2100. Thecentral waistband panel 2100 preferably comprises a stretch laminate,more preferably a zero strain stretch laminate, such as are described inabove-referenced U.S. Pat. No. 5,151,092. The central waistband panel2100 thus comprises a portion of the topsheet 24, a portion of thebacksheet 26, and an elastomeric member 2104 positioned between thetopsheet 24 and the backsheet 26, all of which have been mechanicallystretched. (It should be noted that the central waistband panel has alsobeen passed through the SELF process; however, the bands and pleats havenot been shown in the drawing for simplicity purposes.) The ear panels2102 each comprise a SELF web to further enhance the stretchability andextensibility of the extensible front waist feature 2142. Each ear panelSELF web is similar to the SELF webs described with respect to use forany of the panels of the back waist feature 32. This provides ease ofmanufacture since the ear panel SELF webs can be formed simultaneouslywith the central waistband panel 34 of the extensible back waist feature32 of the previous diaper during continuous manufacture. Further, forease of manufacture, the central waistband panel 34 of the back waistfeature 32 may alternatively comprise a stretch laminate, preferably azero strain stretch laminate, so that the same piece of elastic materialmay form the elastomeric member forming both central waistband panels.The primary fastening system of the closure system comprises a landingmember comprising a reinforcing strip 2041 having a chevron shape. Theclosure system additionally comprises a waist closure system, includingthe first attachment components 2106, for providing tension through theextensible front waist feature 2142.

[0148]FIG. 22 shows a further alternative embodiment of an extensiblefront waist feature 2242 of the present invention. The front waist panel2243 comprises a central waistband panel 2200, a tummy panel 2204, and apair of ear panels 2202. The central waistband panel 2200 is preferablya zero strain stretch laminate as described herein with respect to FIG.21. The ear panels 2202 are also similar to the ear panels 2102 shown inFIG. 21. The tummy panel 2204 extends longitudinally inwardly from thecentral waistband panel 2200 and comprises a SELF web. The SELF web ofthe tummy panel 2204 can be the same or similar to the SELF web of theear panels or it can have less extension forces than the ear panels.

[0149]FIG. 23 shows another alternative embodiment of an extensiblefront waist feature 2342 of the present invention. The front waist panel2343 comprises a central waistband panel 2300, a tummy panel 2304, and apair of ear panels 2302 on either longitudinal side of the centralwaistband panel 2300. In this embodiment, the tummy panel 2304 comprisesa stretch laminate, preferably a zero strain stretch laminate,comprising an elastomeric member 2104. The central waistband panel 2300and the ear panels 2302 each preferably comprise a SELF web. The centralwaistband panel 2300 extends longitudinally inwardly from the end edge48 from about 6 mm to about 25 mm, preferably about 12 mm. Theforce/extension properties of each SELF web may be the same or bedifferent depending upon the desired extensibility of each panel. In theembodiment shown in FIG. 23, each of the SELF webs preferably has thesame extension force properties. This front waist feature 2342 thus hasa “SELF window.” This front waist feature thus reduces sagging sincethere is no elastic adjacent the end edges to pull down the waist. (Inan alternative embodiment of this configuration, the extensible backwaist feature may have arcuate shape or angled to the lateral directionbands and pleats for the SELF webs to provide force resolution andextensibility at an angle to the lateral direction.

[0150]FIG. 24 shows a further alternative embodiment of an extensiblefront waist feature 2442 of the present invention. The front waist panel2443 comprises a central waistband panel 2400, a pair of ear panels2402, a tummy panel 2406, and a landing panel 2408. The centralwaistband panel 2400 comprises a stretch laminate, preferably a zerostrain stretch laminate comprising an elastomeric member 2104. The earpanels 2402, the tummy panel 2406, and the landing panel 2408 eachcomprise a SELF web. The landing panel 2408 extends longitudinallyinwardly from and preferably beyond the landing member of the primaryfastening system. As shown in FIG. 24, the landing member comprises apair of reinforcing strips 2441 laterally spaced from each other andpositioned on the diaper at an angle to the lateral direction. Thelanding panel SELF web is laterally bounded by the reinforcing strips2441 to provide stretch and extensibility between the reinforcing strips2441.

[0151] Test Methods

[0152] Surface-Pathlength

[0153] Pathlength measurements of formed material regions are to bedetermined by selecting and preparing representative samples of eachdistinct region and analyzing these samples by means of microscopicimage analysis methods.

[0154] Samples are to be selected so as to be representative of eachregion's surface geometry. Generally, the transition regions should beavoided since they would normally contain features of both the first andsecond regions. The sample to be measured is cut and separated from theregion of interest. The “measured edge” is to be cut parallel to aspecified axis of elongation interest. Usually this axis is parallel tothe formed primary-axis of either the first region or the second region.An unstrained sample length of one-half inch is to be “gauge marked”perpendicular to the “measured edge”: while attached to the webmaterial, and then accurately cut and removed from the web material.

[0155] Measurement samples are then mounted onto the long-edge of amicroscopic glass slide. The “measured edge” is to extend slightly(approximately 1 mm) outward from the slide edge. A thin layer ofpressure-sensitive adhesive is applied to the glass face-edge to providea suitable sample support means. For highly formed sample regions it hasbeen found desirable to gently extend the sample in its axial direction(without imposing significant force) simultaneous to facilltate contactand attachment of the sample to the slide-edge. This allows improvededge identification during image analysis and avoids possible “crumpled”edge portions that require additional interpretation analysis.

[0156] Images of each sample are to be obtained as “measured edge” viewstaken with the support slide “edge on” using suitable microscopicmeasuring means of sufficient quality and magnification. Data hereinpresented was obtained using the following equipment; Keyence VH-6100(20× Lens) video unit, with video-image prints made with a Sony Videoprinter Mavigraph unit. Video prints were image-scanned with a HewlettPackard ScanJet IIP scanner. Image analysis was on a Macintosh IICicomputer utilizing the software NIH MAC Image version 1.45.

[0157] Using this equipment, a calibration image initially taken of agrid scale length of 0.500″ with 0.005″ increment-marks to be used forcalibration setting of the computer image analysis program. All samplesto be measured are then video-imaged and video-image printed. Next, allvideo-prints are image-scanned at 100 dpi (256-level gray scale) into asuitable Mac image-file format. Finally, each image-file (includingcalibration file) is analyzed utilizing Mac Image 1.45 computer program.All samples are measured with freehand line-measurement tool selected.Samples are measured on both side-edges and the lengths recorded. Simplefilm-like (thin & constant thickness) samples require only one end-edgeto be measured. Laminate and thick foam samples are measured on bothside-edges. Length measurement tracings are to be made along the fullgage length of cut sample. In cases of highly deformed samples, multiple(partially overlapping) images may be required to cover the entire cutsample. In these cases, select characteristic features common to bothoverlapping-images and utilize as “markers” to permit image lengthreadings to adjoin but not overlap.

[0158] The final determination of surface-pathlength for each region isobtained by averaging the lengths of five (5) separate ½″ gage-samplesof each region. Each gage-sample “surface-pathlength” is to be theaverage of both side-edge surface pathlengths.

[0159] Poisson's Lateral Contraction Effect

[0160] The Poisson's lateral contraction effect is measured on anInstron Model 1122, as available from Instron Corporation of Canton,Mass., which is interfaced to a Gateway 2000 486/33 Hz computeravailable from Gateway 2000 of N. Sioux City, S. Dak., using Test Works™software which is available from Sintech, Inc. of Research TrianglePark, N.C. All essential parameters needed for testing are input in theTestWorks™ software for each test. Data collection is accomplishedthrough a combination of manual sample width measurements, andelongation measurements made within TestWorks™.

[0161] The samples used for this test are 1″ wide×4″ long with the longaxis of the sample cut parallel to the direction of the first region ofthe sample. The sample should be cut with a sharp knife or suitablysharp cutting device designed to cut a precise 1″ wide sample. It isimportant that a “representative sample” should be cut so that an arearepresentative of the symmetry of the overall pattern of the deformedregion is represented. There will be cases (due to variations in eitherthe size of the deformed portion or the relative geometries of regions 1and 2) in which it will be necessary to cut either larger or smallersamples than is suggested herein. In this case, it is very important tonote (along with any data reported) the size of the sample, which areaof the deformed region it was taken from and preferably include aschematic of the representative area used for the sample. In general, an“aspect ratio” of (2:1) for the actual extended tensile portion (11:w1)is to be maintained if possible. Five samples are tested.

[0162] The grips of the Instron consist of air actuated grips designedto concentrate the entire gripping force along a single lineperpendicular to the direction of testing elongation having one flatsurface and an opposing face from which protrudes a half round. Noslippage should be permitted between the sample and the grips. Thedistance between the lines of gripping force should be 2″ as measured bya steel rule held beside the grips. This distance will be referred tofrom here on as the “gauge length”.

[0163] The sample is mounted in the grips with its long axisperpendicular to the direction of applied elongation. An arearepresentative of the overall pattern geometry should be symmetricallycentered between the grips. The crosshead speed is set to 10 in/min. Thecrosshead moves to the specified strain (measurements are made at both20 and 60% elongation). The width of the sample at its narrowest point(w2) is measured to be the nearest 0.02″ using a steel rule. Theelongation in the direction of applied extension is recorded to thenearest 0.02″ on the TestWorks software. The Poisson's LateralContraction Effect (PLCE) is calculated using the following formula:${PLCE} = \frac{{W2} - {W1}}{\frac{W1}{\frac{12 - 11}{12}}}$

[0164] where

[0165] w₂=The width of the sample under an applied longitudinalelongation;

[0166] w₁=The original width of the sample;

[0167] l₂=The length of the sample under an applied longitudinalelongation; and

[0168] l₁=The original length of the sample (gauge length);

[0169] Measurements are made at both 20 and 60% elongation using fivedifferent samples for each given elongation. The PLCE at a given percentelongation is the average of five measurements.

[0170] Hysteresis Test

[0171] The hysteresis test is used for measuring the percent set andpercent force relaxation of a material. The tests are performed on anInstron Model 1122, available from Instron Corporation of Canton, Mass.which is interfaced to a Gateway 2000 486/33 Hz computer available fromGateway 2000 of N. Sioux City, S. Dak. 57049, using TestWorks™ softwarewhich is available from Sintech, Inc. of Research Triangle Park, N.C.27709. All essential parameters needed for testing are input in theTestWorks™ software for each test (i.e., Crosshead Speed, Maximumpercent elongation Point and Hold Times). Also, all data collection,data analysis and graphing are done using the TestWorks™ software.

[0172] The samples used for this test are 1″ wide×4″ long with the longaxis of the sample cut parallel to the direction of maximumextensibility of the sample. The sample should be cut with a sharpexacto knife or some suitably sharp cutting device design to cut aprecise 1″ wide sample. (If there is more than one direction ofelongation of the material, samples should be taken parallel torepresentative directions of elongation.) The sample should be cut sothat an area representative of the symmetry of the overall pattern ofthe deformed region is represented. There will be cases (due tovariations in either the size of the deformed portion or the relativegeometries of the first and second regions) in which it will benecessary to cut either larger or smaller samples than is suggestedherein. In this case, it is very important to note (along with any datareported) the size of the sample, which area of the deformed region itwas taken from and preferably include a schematic of the representativearea used for the sample. Three separate tests at 20, 60 and 100% strainare typically measured for each material. Three samples of a givenmaterial are tested at each percent elongation.

[0173] The grips of the Instron consist of air actuated grips designedto concentrate the entire gripping force along a single lineperpendicular to the direction of testing stress having one flat surfaceand an opposing face from which protrudes a half round to minimizeslippage of the sample. The distance between the lines of gripping forceshould be 2″ as measured by a steel rule held beside the grips. Thisdistance will be referred to from hereon as the “gauge length”. Thesample is mounted in the grips with its long axis perpendicular to thedirection of applied percent elongation. The crosshead speed is set to10 in/min. The crosshead moves to the specified maximum percentelongation and holds the sample at this percent elongation for 30seconds. After the thirty seconds the crosshead returns to its originalposition (0% elongation) and remains in this position for 60 seconds.The crosshead then returns to the same maximum percent elongation as wasused in the first cycle, holds for thirty seconds and then again returnsto zero.

[0174] A graph of two cycles is generated. A representative graph isshown in FIG. 7. The percent force relaxation is determined by thefollowing calculation of the force date from the first cycle:${\frac{{{Force}\quad {at}\quad {{Max}.\quad \%}\quad {elongation}} - {{Force}\quad {after}\quad 30\quad {\sec.\quad {hold}}}}{{Force}\quad {at}\quad {Maximum}\quad \% \quad {elongation}\quad \left( {{cycle}\quad 1} \right)} \times 100} = {\% \quad {Force}\quad {Relaxation}}$

[0175] The percent set is the percent elongation of the sample of thesecond cycle where the sample starts to resist the elongation. Thepercent set and the percent force relaxation are shown graphically alsoin FIGS. 7 and 15. The average percent force relaxation and percent setfor three samples is reported for each maximum percent elongation valuetested.

[0176] Tensile Test

[0177] The tensile test is used for measuring extension force (force)versus percent elongation properties and percent available stretch of amaterial. The tests are performed on an Instron Model 1122, availablefrom Instron Corporation of Canton, Mass. which is interfaced to aGateway 2000 486/33 Hz computer available from Gateway 2000 of N. SiouxCity, S. Dak., using TestWorks™ software which is available fromSintech, Inc. of Research Triangle Park, N.C. All essential parametersneeded for testing are input in the TestWorks™ software for each test.Also, all data collection, data analysis and graphing are done using theTestWorks™ software.

[0178] The samples used for this test are 1″ wide×4″ long with the longaxis of the sample cut parallel to the direction of maximumextensibility of the sample. The sample should be cut with a sharpexacto knife or some suitably sharp cutting device designed to cut aprecise 1″ wide sample. (If there is more than one direction ofextensibility of the material, samples should be taken parallel to arepresentative direction of elongation). The sample should be cut sothat an area representative of the symmetry of the overall pattern ofthe deformed region is represented. There will be cases (due tovariations in either the size of the deformed portion or the relativegeometries of the first and second regions) in which it will benecessary to cut either larger or smaller samples than is suggestedherein. In this case, it is very important to note (along with any datareported) the size of the sample, which area of the deformed region itwas taken from and preferably include a schematic of the representativearea used for the sample. Three samples of a given material are tested.

[0179] The grips of the Instron consist of air actuated grips designedto concentrate the entire gripping force along a single lineperpendicular to the direction of testing stress having one flat surfaceand an opposing face from which protrudes a half round to minimizeslippage of the sample. The distance between the lines of gripping forceshould be 2″ as measured by a steel rule held beside the grips. Thisdistance will be referred to from hereon as the “gauge length”. Thesample is mounted in the grips with its long axis perpendicular to thedirection of applied percent elongation. The crosshead speed is set to10 in/m in. The crosshead elongates the sample until the sample breaksat which point the crosshead stops and returns to its original position(0 % elongation).

[0180] The percent available stretch is the point at which there is aninflection in the force-elongation curve, beyond which point there is arapid increase in the amount of force required to elongate the samplefurther. The average of the percent available stretch for three samplesis recorded.

[0181] While the test methods described above are useful for many of theweb materials of the present invention it is recognized that the testmethods may have to be modified to accommodate some of the more complexweb materials within the scope of the present invention.

[0182] While particular embodiments of the present invention have beenillustrated and described, it would be obvious to those skilled in theart that various other changes and modifications can be made withoutdeparting from the spirit and scope of the invention. It is thereforeintended to cover in the appended claims all such changes andmodifications that are within the scope of this invention.

What is claimed is:
 1. A nonwoven web comprising: a plurality of firstregions and a plurality of second regions comprised of the same materialand being visually distinct from each other, wherein the first regionswill exhibit resistive forces in response to an applied elongation alongat least one axis before a substantial portion of the second regionsdevelop significant resistive forces to the applied elongation.
 2. Thenonwoven web of claim 1 wherein the first regions are substantiallyplanar.
 3. The nonwoven web of claim 1 wherein the second regionscomprise rib-like elements.
 4. A nonwoven web material exhibiting atleast two-stages of resistive forces to an applied axial elongationalong at least one axis when subjected to the applied axial elongationin a direction substantially parallel to the axis, the web materialcomprising: a strainable network of visually distinct regions, saidstrainable network including at least a first region which issubstantially planar and a second region containing rib-like elements,said first region and said second region being comprised of the samematerial composition.
 5. A nonwoven web comprising: a plurality of firstregions and a plurality of second regions comprised of the same materialand being visually distinct from each other, said first regionsundergoing substantially molecular-level or fiber-level deformation andsaid second regions initially undergoing a substantially geometricdeformation when said nonwoven web is subjected to an applied elongationalong at least one axis.
 6. The nonwoven web of 5 wherein the firstregions are substantially planar.
 7. The nonwoven web of 5 wherein thesecond regions comprised rib-like elements.
 8. The nonwoven web materialof 5 wherein said nonwoven web material has a first surface and anopposite facing second surface.
 9. The nonwoven web of 8 wherein thefirst regions comprise from about 10% to about 90% of said first surface10. The nonwoven web of 5 wherein the applied elongation is between 10and 25%.